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THE 


WONDERS  OF  LIFE 


A   POPULAR   STUDY 
OF     BIOLOGICAL     PHILOSOPHY 


BY 

ERNST   HAECKEL 

(Ph.D.,  M.D.,  LL.D.,  Sc.D.,  and  Professor  at  the 
University  of  Jena) 

AUTHOR   OF 

••THE   RIDDLE  OF  THE   UNIVERSE" 

"THE  HISTORY  OF  CREATION" 

"  THE  EVOLUTION  OF  MAN  " 

ETC. 


TRANSLATED  BY 
JOSEPH    McCABE 

SUPPLEMENTARY  VOLUME  TO 
"THE   RIDDLE  OF  THE   UNIVERSE" 


«^ 


\^o'^ 


HARPER    &    BROTHERS    PUBLISHERS 
NEW  YORK  AND  LONDON 


Copyright,  1904,  by  Harper  &  Brothers. 

Alt  rights  reserved. 
Published  January,  1905. 


CONTENTS 


Part   I.— METHODOLOGICAL    SECTION: 
KNOWLEDGE    OF    LIFE 

PAGE 

Preface    v 

CHAPTER  I 
Truth i 

CHAPTER  II 
Life 27 

CHAPTER  III 
Miracles 54 

CHAPTER  IV 
The  Science  of  Life 77 

CHAPTER  V 
Death 97 

Part   II.— MORPHOLOGICAL   SECTION: 
NATURE    OF    LIFE 

CHAPTER  VI 
Plasm 121 

CHAPTER  VII 
Unities  of  Life    : 147 

CHAPTER  VIII 
Forms  of  Life 170 

CHAPTER  IX 

MONERA 190 

*"  87330 


CONTENTS 

Part    III.— PHYSIOLOGICAL   SECTION: 
FUNCTIONS   OF   LIFE 

PAGE 

CHAPTER  X 
Nutrition 210 

CHAPTER  XI 
Reproduction 239 

CHAPTER  XII 
Movement 258 

CHAPTER  XIII 
Sensation 287 

CHAPTER  XIV 
Mental  Life 315 

Part  IV.— CxENEALOGICAL  SECTION: 
HISTORY   OF   LIFE 

CHAPTER  XV 
The  Origin  op  Life 336 

CHAPTER  XVI 
The  Evolution  of  Life 359 

CHAPTER  XVII 
The  Value  of  Life S^^ 

CHAPTER  XVIII 
Morality 4ii 

CHAPTER  XIX 
Dualism 433 

CHAPTER  XX 
Monism 452 

Index 475 


PREFACE 


THE  publication  of  the  present  work  on  The  Won- 
ders of  Life  has  been  occasioned  by  the  success  of 
The  Riddle  of  the  Universe,  which  I  wrote  five  years 
ago.  Within  a  few  months  of  the  issue  of  this  study 
of  the  monistic  philosophy,  in  the  autumn  of  1899,  ten 
thousand  copies  were  sold.  Moreover,  the  publisher 
having  been  solicited  on  many  sides  to  issue  a  popular 
edition  of  the  work,  more  than  a  hundred  thousand 
copies  of  this  were  sold  within  a  year.^  This  extraor- 
dinary and — as  far  as  I  was  concerned — unexpected 
success  of  a  philosophical  work  which  was  by  no  means 
light  reading,  and  which  had  no  particular  charm  of 
presentation,  affords  ample  proof  of  the  intense  interest 
taken  by  even  the  general  reader  in  the  object  of  the 
work — the  construction  of  a  rational  and  solid  philos- 
ophy of  life. 

Naturally,  the  clear  opposition  of  my  monistic  philos- 
ophy, based  as  it  was  on  the  most  advanced  and  sound 
scientific  knowledge,  to  the  conventional  ideas  and  to  an 
outworn  "revelation,"  led  to  the  publication  of  a  vast 
number  of  criticisms  and  attacks.  During  the  first  twelve 
months  more  than  a  hundred  reviews  and  a  dozen  large 
pamphlets  appeared,  full  of  the  most  contradictory 
strictures  and  the  most  curious  observations.     One  of 

*  The  English  translation  met  with  almost  equal  success. 
Nearly  one  hundred  thousand  copies  of  the  cheap  edition  have 
already  been  sold. — Trans. 

V 


PREFACE 

the  ablest  of  my  pupils,  Heinrich  Schmidt,  gave  a  sum- 
mary and  criticism  of  them  in  his  Der  Kampf  urn  die 
Weltrdthsel,  in  the  autumn  of  1900.  However,  the 
literary  struggle  went  on  to  assume  gigantic  proportions 
when  twelve  different  translations  of  the  Riddle  appeared, 
and  led  to  an  ever-increasing  agitation  in  every  educated 
country  of  the  Old  and  the  New  World. 

I  gave  a  brief  reply  to  the  chief  of  these  attacks  in 
April,  1903,  in  the  appendix  to  the  popular  edition  of  the 
Riddle.  It  would  be  useless  to  go  further  into  this  con- 
troversy and  meet  the  many  attacks  that  have  since  been 
made.  It  is  a  question  here  of  that  profound  and  irre- 
concilable opposition  between  knowledge  and  faith, 
between  a  real  knowledge  of  nature  and  an  alleged 
"revelation,"  which  has  occupied  the  thoughtful  and 
inquiring  mind  for  thousands  of  years.  I  base  my 
monistic  philosophy  exclusively  on  the  convictions  which 
I  have  gained  during  fifty  years'  close  and  indefatigable 
study  of  nature  and  its  harmonious  working.  My  dual- 
istic  opponents  grant  only  a  restricted  value  to  these 
experiences;  they  would  subordinate  them  to  the  fan- 
tastic ideas  which  they  have  reached  by  faith  in  a  super- 
natural world  of  spirits.  An  honest  and  impartial  con- 
sideration of  this  palpable  contradiction  discovers  it  to 
be  irreconcilable — either  science  and  experience,  or  faith 
and  revelation! 

For  this  reason  I  do  not  propose  to  make  any  further 
reply  to  the  opponents  of  The  Riddle  of  the  Universe,  and 
I  am  still  less  disposed  to  take  up  the  personal  attacks 
which  some  of  my  critics  have  thought  fit  to  make  on 
me.  In  the  course  of  this  controversy  I  have  grown 
painfully  familiar  with  the  means  with  which  it  is  sought 
to  silence  the  detested  free-thinker — misrepresentation, 
sophistry,  calumny,  and  denunciation.  ' '  Critical ' '  philos- 
ophers of  the  modern  Kantist  school  vie  in  this  with 
orthodox  theologians.     What  I  have  said  in  this  con- 

vi 


PREFACE 

nection  of  the  theologian  Loofs,  of  Halle,  the  philologist 
Dennert,  of  Godesberg,  and  the  metaphysician  Paulsen, 
of  Berlin,  in  the  appendix  to  the  cheap  German  edition 
of  the  Riddle,  applies  equally  to  many  other  opponents 
of  the  same  type.  These  heated  partisans  may  continue 
to  attack  and  calumniate  my  person  as  they  will;  they 
will  not  hurt  the  sacred  cause  of  truth  in  which  I 
labor. 

Much  more  interesting  to  me  than  these  attacks  were 
the  innumerable  letters  which  I  have  received  from 
thoughtful  readers  of  the  Riddle  during  the  last  five 
years,  and  particularly  since  the  appearance  of  a  popular 
edition.  Of  these  I  have  already  received  more  than  five 
thousand.  At  first  I  conscientiously  replied  to  each  of 
these  correspondents,  but  I  had  at  length  to  content 
myself  with  sending  a  printed  slip  with  the  intimation 
that  my  time  and  strength  did  not  permit  me  to  make 
an  adequate  reply.  However,  though  this  correspond- 
ence was  very  exacting,  it  afforded  a  very  welcome  proof 
of  the  lively  sympathy  of  a  large  number  of  readers  with 
the  aim  of  the  monistic  philosophy,  and  a  very  interest- 
ing insight  into  the  mental  attitude  of  the  most  varied 
classes  of  readers.  I  especially  noticed  that  the  same  re- 
marks and  questions  occurred  in  many  of  these  five 
thousand  letters,  very  often  expressed  in  the  same  terms. 
Most  of  the  inquiries  related  to  biological  questions, 
which  I  had  cursorily  and  inadequately  touched  both 
in  The  Riddle  of  the  Universe  and  The  History  of  Cre- 
ation. The  natural  desire  to  remedy  these  deficien- 
cies of  my  earlier  writings  and  give  a  general  reply 
to  my  interrogators  was  the  immediate  cause  of 
the  writing  of  the  present  work  on  The  Wonders  of 
Life. 

I  was  confirmed  in  this  design  by  the  circumstance 
that  another  scientist,  the  botanist  Johannes  Reinke,  of 
Kiel,  had  published  two  works  in  which  he  had  treated 

vii 


PREFACE 

the  general  problems  of  natural  philosophy,  especially 
of  biology,  from  a  purely  dualistic  and  teleological  point 
of  view;  these  works  were  his  Die  Welt  ah  That  (1899) 
and  Einleitimg  in  die  theoretische  Biologie  (1902).  As 
both  these-  works  are  well  written  and  present  the 
principles  of  dualism  and  teleology  with  admirable  con- 
sistency— as  far  as  this  is  possible — it  seemed  to  me 
that  it  was  desirable  to  give  a  thorough  exposition  of  my 
own  monistic  and  causative  system. 

Hence  the  present  work  on  the  wonders  of  life  is,  as 
the  title  indicates,  a  supplementary  volume  to  The 
Riddle  of  the  Universe.  While  the  latter  undertook  to 
make  a  comprehensive  survey  of  the  general  questions  of 
science — as  cosmological  problems — in  the  light  of  the 
monistic  philosophy,  the  present  volume  is  confined  to 
the  realm  of  organic  science,  or  the  science  of  life.  It 
seeks  to  deal  connectedly  with  the  general  problems  of 
biology,  in  strict  accord  with  the  monistic  and  me- 
chanical principles  which  I  laid  down  in  1866  in  my 
General  Morphology.  In  this  I  laid  special  stress  on 
the  universality  of  the  law  of  substance  and  the  sub- 
stantial unity  of  nature,  which  I  have  further  treated 
in  the  second  and  fourteenth  chapters  of  The  Riddle  of 
the  Universe. 

The  arrangement  of  the  vast  material  for  this  study  of 
the  wonders  of  life  has  been  modelled  on  that  of  the 
Riddle.  I  have  retained  the  division  into  larger  and 
smaller  sections  and  the  synopses  of  the  various  chapters. 
Thus  the  whole  biological  content  falls  into  four  sections 
and  twenty  chapters.  I  should  much  have  liked  to  add 
illustrations  in  many  parts  of  the  text  to  make  the  sub- 
ject plainer,  especially  as  regards  chapters  vii.,  viii., 
xi.,  and  xvi. ;  but  this  would  have  led  to  a  considerable 
increase  in  the  size  and  price  of  the  book.  Moreover, 
there  are  now  many  illustrated  works  which  will  help 
the  reader  to  go  more  fuhy  into  the  various  sections  of 

viii 


PREFACE 

the  study.  Among  others,  my  History  of  Creation 
(EngHsh  translation)  and  Evolution  of  Man  (EngUsh 
translation  now  in  course  of  preparation)  will  be 
found  helpful  in  this  way.  The  German  reader  will 
also  find  many  illustrations  to  elucidate  the  text  of 
this  book  in  my  recently  completed  work,  Kiinst- 
f  or  men  der  Natur  (lo  parts,  with  loo  tables,  1899- 
1904). 

I  had  said,  in  the  preface  to  The  Riddle  of  the  Universe 
in  1899,  that  I  proposed  to  close  my  study  of  the  monistic 
system  with  that  work,  and  that  "  I  am  wholly  a  child  of 
the  nineteenth  century,  and  with  its  close  I  draw  the 
line  under  my  Hfe's  work."  If  I  now  seem  to  run 
counter  to  this  observation,  I  beg  the  reader  to  consider 
that  this  work  on  the  wonders  of  life  is  a  necessary 
supplement  to  the  widely  circulated  Riddle  of  the  Uni- 
verse, and  that  I  felt  bound  to  write  it  in  response  to  the 
inquiries  of  so  many  of  my  readers.  In  this  second 
work,  as  in  the  earlier  one,  I  make  no  pretension  to  give 
the  reader  a  comprehensive  statement  of  my  monistic 
philosophy  in  the  full  maturity  it  has  reached — for  me 
personally,  at  least  —  at  the  close  of  the  nineteenth 
century.  A  subjective  theory  of  the  world  such  as  this 
can,  naturally,  never  hope  to  have  a  complete  objective 
validity.  My  knowledge  is  incomplete,  like  that  of  all 
other  men.  Hence,  even  in  this  "biological  sketch-book," 
I  can  only  offer  studies  of  unequal  value  and  incomplete 
workmanship.  There  still  remains  the  great  design  of 
embracing  all  the  exuberant  phenomena  of  organic 
life  in  one  general  scheme  and  explaining  all  the 
wonders  of  life  from  the  monistic  point  of  view,  as 
forms  of  one  great  harmoniously  working  universe — 
whether  you  call  this  Nature  or  Cosmos,  World  or 
God. 

The  twenty  chapters  of  The  Wonders  of  Life  were 
written  uninterruptedly  in  the  course  of  four  months 

ix 


PREFACE 

which  I  spent  at  Rapallo,  on  the  shore  of  the  blue 
Mediterranean.  The  quiet  Hfe  in  this  tiny  coast -town  of 
the  ItaHan  Riviera  gave  me  leisure  to  weigh  again  all 
the  views  on  organic  life  which  I  had  formed  by  many- 
sided  experience  of  life  and  learning  since  the  beginning 
of  my  academic  studies  (1852)  and  my  teaching  at  Jena 
(1861).  To  this  I  was  stimulated  by  the  constant  sight 
of  the  blue  Mediterranean,  the  countless  inhabitants  of 
which  had,  for  fifty  years,  afforded  such  ample  material 
for  my  biological  studies;  and  my  solitary  walks  in  the 
wild  gorges  of  the  Ligurian  Apennines,  and  the  moving 
spectacle  of  its  forest-crowned  mountain  altars,  inspired 
me  with  a  feeling  of  the  unity  of  living  nature — a  feeling 
that  only  too  easily  fades  away  in  the  study  of  detail  in 
the  laboratory.  On  the  other  hand,  such  a  situation  did 
not  allow  a  comprehensive  survey  of  the  boundless 
literature  which  has  been  evoked  by  the  immense  ad- 
vances in  every  branch  of  biology.  However,  the 
present  work  is  not  intended  to  be  a  systematic 
manual  of  general  biology.  In  the  revision  of  the 
text,  on  which  I  was  engaged  during  the  summer  at 
Jena,  I  had  to  restrict  myself  to  occasional  additions 
and  improvements.  In  this  I  had  the  assistance  of 
my  worthy  pupil,  Dr.  Heinrich  Schmidt,  to  whom 
also  I  am  indebted  for  the  careful  revision  of  the 
proofs. 

When  I  completed  my  seventieth  year  at  Rapallo,  on 
February  i6th,  I  was  overwhelmed  with  a  mass  of  con- 
gratulations, letters,  telegrams,  flowers,  and  other  gifts, 
most  of  which  came  from  unknown  readers  of  The 
Riddle  of  the  Universe  in  all  parts  of  the  world.  If  my 
thanks  have  not  yet  reached  any  of  them,  I  beg  to  tender 
them  in  these  lines.  But  I  should  be  especially  gratified 
if  they  would  regard  this  work  on  the  wonders  of  life  as 
an  expression  of  my  thanks,  and  as  a  literary  gift  in 
return.     May  my  readers  be  moved  by  it  to  penetrate 

X 


PREFACE 

deeper  and  deeper  into  the  glorious  work  of  Nature,  and 
to  reach  the  insight  of  our  greatest  German  natural 
philosopher,  Goethe: 

"What  greater  thing  in  life  can  man  achieve 
Than  that  God-Nature  be  revealed  to  him?" 

Ernst  Haeckel. 
Jena,  June  17, 1^04. 


THE  WONDERS  OF  LIFE 


THE   WONDERS   OF   LIFE 


I 

TRUTH 

Truth  and  the  riddle  of  the  universe — Experience  and  thought 
—  Empiricism  and  speculation  —  Natural  philosophy  — 
Science — Empirical  science — Descriptive  science — Observa- 
tion and  experiment — History  and  tradition — Philosophic 
science — Theory  of  knowledge — Knowledge  and  the  brain — 
^stheta  and  phroneta  —  Seat  of  the  soul,  or  organ  of 
thought:  phronema — Anatomy,  physiology,  ontogeny,  and 
phylogeny  of  the  phronema — Psychological  metamorphoses 
— Evolution  of  consciousness — Monistic  and  dualistic  theories 
of  knowledge — Divergence  of  the  two  ways  of  attaining  the 
truth. 

WHAT  is  truth  ?  This  great  question  has  occupied 
the  more  thoughtful  of  men  for  thousands  of  years, 
and  elicited  myriads  of  attempts  to  answer  it,  myriads 
of  truths  and  untruths.  Every  history  of  philosophy 
gives  a  longer  or  shorter  account  of  these  countless 
efforts  of  the  advancing  mind  of  man  to  attain  a  clear 
knowledge  of  the  world  and  of  itself.  Nay,  even 
''world-wisdom"  itself,  or  philosophy  in  the  proper 
sense  of  the  word,  is  nothing  but  a  connected  effort  to 
unite  the  general  results  of  man's  investigation,  ob- 
servation, reflection,  and  thought,  and  bring  them  to  a 
common  focus.  Without  prejudice  and  without  fear, 
philosophy  would  tear  the  mantle  from  "the  veiled 
statue  of  Sais,"  and  attain  a  full  vision  of  the  truth. 


t5,  H.  H!LL  LIBRARY 

North  Carolina  state  College 


THE     WONDERS     OF     LIFE 

True    philosophy,    taken    in   this    sense,    may    proudty 
and  justly  style  itself  "the  queen  of  the  sciences." 

When  philosophy,  as  a  search  for  truth  in  the  highest 
sense,  thus  unites  our  isolated  discoveries  and  seeks 
to  weld  them  into  one  unified  system  of  the  world,  it 
comes  at  length  to  state  certain  fundamental  problems, 
the  answer  to  which  varies  according  to  the  degree  of 
culture  and  the  point  of  view  of  the  inquirer.  These 
final  and  highest  objects  of  scientific  inquiry  have  been 
of  late  comprehended  under  the  title  of  The  Riddle  of 
the  Universe,  and  I  gave  this  name  to  the  work  I  pub- 
lished in  1899,  which  dealt  with  them,  in  order  to  make 
its  aim  perfectly  clear.  In  the  first  chapter  I  dealt 
briefly  with  what  have  been  called  "the  seven  great 
cosmic  problems,"  and  in  the  twelfth  chapter  I  en- 
deavored to  show  that  they  may  all  be  reduced  to  one 
final  "problem  of  substance,"  or  one  great  "riddle  of  the 
universe."  The  general  formulation  of  this  problem  is 
effected  by  blending  the  two  chief  cosmic  laws — the 
chemical  law  of  the  constancy  of  matter  (Lavoisier, 
1789),  and  the  physical  law  of  the  constancy  of  force 
(Robert  Mayer,  1842).  This  monistic  association  of  the 
two  fundamental  laws,  and  establishment  of  the  unified 
law  of  substance,  has  met  with  a  good  deal  of  agree- 
ment, but  also  with  some  opposition;  but  the  most 
violent  attacks  were  directed  against  my  monistic 
theory  of  knowledge,  or  against  the  method  I  followed 
in  seeking  to  solve  the  riddle  of  the  universe.  The  only 
paths  which  I  had  recognized  as  profitable  were  those 
of  experience  and  thought — or  empirical  knowledge  and 
speculation.  I  had  insisted  that  these  two  methods 
supplemented  each  other,  and  that  they  alone,  under 
the  direction  of  reason,  lead  to  the  attainment  of  truth. 
At  the  same  time  I  had  rejected  as  false  two  other  much- 
frequented  paths  which  purported  to  lead  directly  to  a 
profounder  knowledge,  the  ways  of  emotion  and  re  vela- 


TRUTH 

tion;  both  of  these  are  in  opposition  to  reason,  since  they 
demand  a  behef  in  miracles. 

"All  natural  science  is  philosophy,  and  all  true  philos- 
ophy is  natural  science.  All  true  science  is  natural  phil- 
osophy.' '  I  expressed  in  these  words  the  general  result  of 
my  monistic  studies  in  1866  (in  the  twenty-seventh  chap- 
ter of  my  Gcnerelle  Morphologic) .  I  then  laid  it  down  as 
the  fundamental  principle  of  the  monistic  system  that 
the  unity  of  nature  and  the  unity  of  science  follow  abso- 
lutely from  any  connected  study  of  modern  philosophic 
science,  and  I  expressed  my  conviction  in  these  terms: 
"All  human  science  is  knowledge  based  on  experience, 
or  empirical  philosophy;  or,  if  the  title  be  preferred, 
philosophic  empiricism.  Thoughtful  experience,  or 
thought  based  on  experience,  is  the  only  way  and 
method  to  be  followed  in  the  search  for  truth."  I 
endeavored  to  establish  these  theses  conclusively  in  the 
first  book  of  the  Generelle  Morphologie,  which  contains 
(p.  108)  a  critical  and  methodological  introduction  to  this 
science.  Not  only  are  those  methods  considered  "which 
must  necessarily  supplement  each  other"  (I.  Empiricism 
and  Philosophy;  II.  Analysis  and  Synthesis;  III.  In- 
duction and  Deduction),  but  also  those  "which  neces- 
sarily exclude  each  other"  (IV.  Dogmatism  and  Criti- 
cism; V.  Teleology  and  Causality,  or  Vitalism  and  Me- 
chanicism;  VI.  Dualism  and  Monism).  The  monistic 
principles  which  I  developed  there  thirty-eight  years 
ago  have  only  been  confirmed  by  my  subsequent  labors, 
and  so  I  may  refer  the  interested  reader  to  that  work. 
The  Riddle  of  the  Universe  is  in  the  main  an  attempt  to 
introduce  to  the  general  reader  in  a  convenient  form  the 
chief  points  of  the  monistic  system  I  established.  How- 
ever, the  opposition  which  has  been  aroused  by  the 
general  philosophic  observations  of  the  Riddle  compels 
me  to  give  a  further  explanation  of  the  chief  features 
of  my  theory  of  knowledge. 

3 


THE    WONDERS    OF    LIFE 

All  true  science  that  deserves  the  name  is  based  on 
a  collection  of  experiences,  and  consists  of  conclusions 
that  have  been  reached  by  a  rational  connection  of  these 
experiences.  "Only  in  experience  is  there  truth,"  says 
Kant.  The  external  world  is  the  object  that  acts  on 
man's  organs  of  sense,  and  in  the  internal  sense-centres  of 
the  cortex  of  the  brain  these  impressions  are  subjectively 
transformed  into  presentations.  The  thought-centres,  or 
association  centres,  of  the  cortex  (whether  or  no  one  dis- 
tinguishes them  from  the  sense-centres)  are  the  real 
organs  of  the  mind  that  unite  these  presentations  into 
conclusions.  The  two  methods  of  forming  these  con- 
clusions— induction  and  deduction,  the  formation  of 
arguments  and  concepts,  thought  and  consciousness — 
make  up  together  the  cerebral  function  we  call  reason. 
These  long  familiar  and  fundamental  truths,  the  rec- 
ognition of  which  I  have  described  for  thirty  -  eight 
years  as  the  first  condition  for  solving  the  riddle  of  life, 
are  still  far  from  being  generally  appreciated.  On  the 
contrary,  we  find  them  combated  by  the  extreme  rep- 
resentatives of  both  tendencies  of  science.  On  the 
one  side,  the  empirical  and  descriptive  school  would 
reduce  the  whole  task  to  experience,  without  calling 
in  the  aid  of  philosophy ;  while  philosophic  speculation, 
on  the  other  side,  would  dispense  with  experience  and 
endeavor  to  construct  the  world  by  pure  thought. 

Starting  from  the  correct  principle  that  all  science 
originally  has  its  source  in  experience,  the  representa- 
tives of  "experimental  science"  affirm  that  their  task 
consists  solely  in  the  exact  observation  of  "facts"  and 
the  classification  and  description  of  them,  and  that 
philosophic  speculation  is  nothing  more  than  an  idle 
play  of  ideas.  Hence  this  one-sided  sensualism,  as 
Condillac  and  Hume  especially  maintained  it,  affirmed 
that  the  whole  action  of  the  mind  consists  in  a  manipu- 
lation  of   sense  -  impressions.      This   narrow   empirical 


TRUTH 

conception  spread  very  widely  during  the  nineteenth 
century,  particularly  in  the  second  half,  among  the 
rapidly  advancing  sciences;  it  was  favored  by  the 
specialism  which  grew  up  in  the  necessary  division  of 
labor.  The  majority  of  scientists  are  still  of  opinion 
that  their  task  is  confined  to  the  exact  observation  and 
description  of  facts.  All  that  goes  beyond  this,  and 
especially  all  far-reaching  philosophic  conclusions  from 
their  accumulated  observations,  are  regarded  by  them 
with  suspicion.  Rudolph  Virchow  strongly  emphasized 
this  narrow  empirical  tendency  ten  years  ago.  In  his 
speech  on  the  foundation  of  the  BerUn  University  he 
explained  the  "transition  from  the  philosophic  to  the 
scientific  age";  he  said  that  the  sole  aim  of  science  is 
"the  knowledge  of  facts,  the  objective  investigation  of 
natural  phenomena  in  detail."  The  former  poHtician 
seemed  to  forget  that  he  had  maintained  a  precisely 
opposite  view  forty  years  before  (at  Wiirtzburg),  and 
that  his  own  great  achievement,  the  creation  of  cellular 
pathology,  was  a  philosophic  construction — the  forma- 
tion of  a  new"  and  comprehensive  theory  of  disease  by 
the  combination  of  countless  observations  and  the  con- 
clusions deduced  therefrom. 

No  science  of  any  kind  whatever  consists  solely  in  the 
description  of  observed  facts.  Hence  we  can  only  regard 
it  as  a  pitiful  contradiction  in  terms  when  we  find  biolog}^ 
classed  in  official  documents  to-day  as  a  "descriptive 
science,"  and  physics  opposed  to  it  as  an  "explanatory 
science."  As  if  in  both  cases  we  had  not,  after  de- 
scribing the  observed  phenomena,  to  pass  on  to  trace 
them  to  their  causes — that  is,  to  explain  them — by  means 
of  rational  inferences!  But  it  is  even  more  regrettable 
to  find  that  one  of  the  ablest  scientists  of  Germany, 
Oustav  Kirchhoff,  has  claimed  that  description  is  the 
final  and  the  highest  task  of  science.  The  famous  dis- 
coverer  of   spectrum  analysis   says  in  his  Lectures  on 

5 


THE    WONDERS    OF    LIFE 

Mathematical  Physics  and  Mechanics  (1877):  "It  is  the 
work  of  science  to  describe  the  movements  perceived  in 
Nature,  in  the  most  complete  and  simplest  fashion." 
There  is  no  meaning  in  this  statement  unless  we  take 
the  word  "description"  in  a  quite  unusual  sense — unless 
"complete  description"  is  meant  to  include  explanation. 
For  thousands  of  years  true  science  has  been,  not  merely 
a  simple  description  of  individual  facts,  but  an  explana- 
tion of  them  by  tracing  them  to  their  causes.  It  is  true 
that  our  knowledge  of  them  is  always  imperfect,  or  even 
hypothetical;  but  this  is  equally  true  of  the  description 
of  facts.  Kirchhoff's  statement  is  in  flagrant  contra- 
diction to  his  own  great  achievement,  the  founding  of 
spectrum  analysis;  for  the  extraordinary  significance  of 
this  does  not  lie  in  the  discovery  of  the  wonderful  facts 
of  spectroscopic  optics  and  the  "complete  description" 
of  individual  spectra,  but  in  the  rational  grouping  and 
interpretation  of  them.  The  far-reaching  conclusions 
that  he  has  drawn  from  them  have  opened  out  entirely 
new  paths  to  physics  and  chemistry.  Hence  KirchhofiF 
is  in  as  sad  a  plight  as  Virchow  when  he  formtilates  so 
precarious  a  principle.  However,  these  statements  of  the 
two  great  scientists  have  done  a  great  deal  of  harm,  as 
they  have  widened  still  more  the  deep  gulf  between 
science  and  philosoph}^  It  may  be  of  some  service  if 
a  few  thousand  of  the  thoughtless  followers  of  "de- 
scriptive science  "  are  persuaded  to  refrain  from  attempts 
at  explanation  of  facts.  But  the  master-builders  of 
science  cannot  be  content  with  the  collection  of  dead 
material ;  they  must  press  on  to  the  knowledge  of  causes 
by  a  rational  maniptilation  of  their  facts. 

The  accurate  and  discriminating  observation  of  facts, 
supported  by  careful  experiment,  is  certainly  a  great 
advantage  that  modern  science  has  over  all  earlier  efforts 
to  attain  the  truth.  The  distinguished  thinkers  of  classic 
antiquity  were  far  superior  to  most  modern  scientists 

6 


TRUTH 

and  philosophers  in  regard  to  judgment  and  reasoning, 
or  all  the  subtler  processes  of  thought;  but  they  were 
superficial  and  unpractised  observers,  and  were  barely 
acquainted  with  experiment.  In  the  Middle  Ages  scien- 
tific work  degenerated  in  both  its  aspects,  as  the  domi- 
nant creed  demanded  only  faith  and  the  recognition  of 
its  supernatural  revelation,  and  depreciated  observa- 
tion. The  great  importance  of  this  as  a  foundation  of 
real  knowledge  was  first  appreciated  by  Bacon  of 
Verulam,  whose  Novum  Organon  (1620)  laid  down  the 
principles  of  scientific  knowledge,  in  opposition  to  the 
current  scholasticism  derived  from  Aristotle  and  his 
Organon.  Bacon  became  the  founder  of  modern  em- 
pirical investigation,  not  only  by  making  careful  and 
exact  observation  of  phenomena  the  basis  of  all  philos- 
ophy, but  also  in  demanding  the  supplementing  of 
this  by  experiment;  by  this  experiment  he  understood 
the  putting  of  a  question  to  Nature,  as  it  were,  which  she 
must  herself  answer — a  kind  of  observation  under  defi- 
nite and  deliberate  conditions. 

This  more  rigorous  method  of  "exact  observation," 
which  is  hardly  three  hundred  years  old,  was  very 
strongly  aided  by  the  inventions  which  enable  the 
human  eye  to  penetrate  into  the  farthest  abysses  of 
space  and  the  profoundest  depths  of  smaller  bodies — 
the  telescope  and  microscope.  The  great  improvement 
in  these  instruments  during  the  nineteenth  century,  and 
the  support  given  by  other  recent  inventions,  have  led 
to  triumphs  of  observation  in  this  "century  of  science" 
that  surpassed  all  anticipation.  However,  this  very 
refinement  of  the  technique  of  observation  has  its  draw- 
backs, and  has  led  to  many  an  error.  The  effort  to 
obtain  the  utmost  accuracy  in  objective  observation  has 
often  led  to  a  neglect  of  the  part  which  is  played  by 
the  subjective  mental  action  of  the  observer;  his  judg- 
ment and  reason  have  been  depreciated  in  comparison 

7 


THE    WONDERS    OF    LIFE 

with  the  acuteness  and  clearness  of  his  vision.  Fre- 
quently the  means  has  been  turned  into  the  end  of 
knowledge.  In  the  reproduction  of  the  thing  observed 
the  objective  photograph,  presenting  all  parts  of  the 
object  with  equal  plainness,  has  been  more  valued  than 
the  subjective  design  that  reproduces  only  what  is 
essential  and  leaves  out  what  is  superfluous;  yet  the 
latter  is  in  many  cases  (for  instance,  in  histological 
observation)  much  more  important  and  correct  than 
the  former.  But  the  greatest  fault  has  been  that  many 
of  these  "exact"  observers  have  refrained  altogether 
from  reflection  and  judgment  on  the  phenomena  ob- 
served, and  have  neglected  subjective  criticism;  hence 
it  is  that  so  often  a  number  of  observers  of  the  same 
phenomenon  contradict  each  other,  while  each  one 
boasts  of  the  "exactness"  of  his  observations. 

Like  observation,  experimentation  has  been  wonder- 
fully improved  of  late  years.  The  experimental  sciences 
which  make  most  use  of  it  —  experimental  physics, 
chemistry,  physiology,  pathology,  etc. — have  made  as- 
tounding progress.  But  it  is  just  as  important  in  the 
case  of  experiment — or  observation  under  artificial  con- 
ditions— as  of  simple  observation  that  it  be  undertaken 
and  carried  out  with  a  sound  and  clear  judgment. 
Nature  can  only  give  a  correct  and  unambiguous  answer 
to  the  question  you  put  her  when  it  is  clearly  and  dis- 
tinctly proposed.  This  is  very  often  not  the  case,  and 
the  experimenter  loses  himself  in  meaningless  efforts, 
with  the  foolish  hope  that  "something  may  come  of 
it."  The  modern  province  of  experimental  or  me- 
chanical embryology  is  especially  marred  by  these  use- 
less and  perverse  experiments.  Equally  foolish  is  the 
conduct  of  those  biologists  who  would  transfer  the  ex- 
periment that  is  valuable  in  physiology  to  the  field  of 
anatomy,  where  it  is  rarely  profitable.  In  the  modern 
controversy  about  evolution  the  attempt  is  frequently 

8 


TRUTH 

made  to  prove  or  refute  experimentally  the  origin  of 
species.  It  is  quite  forgotten  that  the  idea  of  species 
is  only  relative,  and  that  no  man  of  science  can  give  an 
absolute  definition  of  it.  Nor  is  it  less  perverse  to 
attempt  to  apply  experimentation  to  historical  problems 
where  all  the  conditions  for  a  successful  application  are 
lacking. 

The  knowledge  which  we  obtain  directly  by  observa- 
tion and  experiment  is  only  sound  when  it  refers  to  pres- 
ent events.  We  have  to  turn  to  other  methods  for  the 
investigation  of  the  past — to  history  and  traditions ;  and 
these  are  less  easily  accessible.  This  branch  of  science 
has  been  investigated  for  thousands  of  years,  as  far  as 
the  history  of  man  and  civilization,  of  peoples  and  states, 
and  their  customs,  laws,  languages,  and  migrations,  is 
concerned.  In  this,  the  oral  and  written  tradition  from 
generation  to  generation,  the  ancient  monuments,  and 
documents,  and  weapons,  etc.,  furnish  an  abounding 
empirical  material  from  which  critical  judgment  can 
draw  a  host  of  conclusions.  However,  the  door  to  error 
lies  wide  open  here,  as  the  documents  are  usually  im- 
perfect, and  the  subjective  interpretation  of  them  is  often 
no  clearer  than  their  objective  validity. 

Natural  history,  properly  so  called,  or  the  study  of  the 
origin  and  past  history  of  the  universe,  the  earth,  and  its 
organic  population,  is  much  more  recent  than  the  history 
of  mankind.  Immanuel  Kant  was  the  first  to  lay  the 
foundations  of  a  mechanical  cosmogony  in  his  remark- 
able Natural  History  of  the  Heavens  (1755),  and  Laplace 
gave  mathematical  shape  to  his  ideas  in  1796.  Geology, 
also,  or  the  story  of  the  evolution  of  the  earth,  was  not 
founded  until  the  beginning  of  the  eighteenth  century, 
and  did  not  assume  a  definite  shape  until  the  time  of 
Hoff  and  Lyell  (1830).  Later  still  (1866)  were  laid  the 
foundations  of  the  science  of  organic  evolution,  when 
Darwin  provided  a  sound  foundation,  in  his  theory  of 

9 


THE    WONDERS    OF    LIFE 

selection,  for  the  theory  of  descent  which  Lamarck  had 
proposed  fifty  years  before. 

In  sliarp  contrast  to  this  purely  empirical  method, 
which  is  favored  by  most  men  of  science  in  our  day,  we 
have  the  purely  speculative  tendency  which  is  current 
among  our  academic  philosophers.  The  great  regard 
which  the  critical  philosophy  of  Immanuel  Kant  obtained 
during  the  nineteenth  century  has  recently  been  in- 
creased in  the  various  schools  of  philosophy.  As  is 
known,  Kant  affirmed  that  only  a  part  of  our  knowl- 
edge is  empirical,  or  a  posteriori — that  is,  derived  from 
experience;  and  that  the  rest  of  our  knowledge  (as,  for 
instance,  mathematical  axioms)  is  a  priori — that  is  to 
say,  reached  by  the  deductions  of  pure  reason,  inde- 
pendently of  experience.  This  error  led  to  the  further 
statement  that  the  foundations  of  science  are  meta- 
physical, and  that,  though  man  can  attain  a  certain 
knowledge  of  phenomena  by  the  innate  forms  of  space 
and  time,  he  cannot  grasp  the  "thing  in  itself"  that  lies 
behind  them.  The  purely  speculative  metaphysics 
which  was  built  up  on  Kant's  apriorism,  and  which 
found  its  extreme  representative  in  Hegel,  came  at 
length  to  reject  the  empirical  method  altogether,  and 
insisted  that  all  knowledge  is  obtained  by  pure  reason, 
independently  of  experience 
I  Kant's  chief  error,  which  proved  so  injurious  to  the 

I     whole  of  subsequent  philosophy,  lay  in  the  absence  of 
I     any  physiological  and  phylogenetic  base  to  his  theory 
of  knowledge;  this  was  only  provided  sixty  years  after 
his  death  by  Darwin's  reform  of  the  science  of  evolution, 
^     and  by  the  discoveries  of  cerebral  physiologists.     He 
^     regarded  the  human  mind,  with  its  innate  quality  of 
reason,  as  a  completely  formed  entity  from  the  first,  and 
I    made  no  inquiry  into  its  historical  development.   Hence, 
"    he  defended  its  immortality  as  a  practical  postulate, 
incapable  of  proof;  he  had  no  suspicion  of  the  evolution 

lO 


i 


TRUTH 

of  man's  soul  from  that  of  the  nearest  related  mammals. 
The  curious  predisposition  to  a  priori  knowledge  is  really 
the  effect  of  the  inheritance  of  certain  structures  of  the 
brain,  which  have  been  formed  in  man's  vertebrate 
ancestors  slowly  and  gradually,  by  adaptation  to  an 
association  of  experiences,  and  therefore  of  a  posteriori 
knowledge.  Even  the  absolutely  certain  truths  of  mathe- 
matics and  physics,  which  Kant  described  as  synthetic 
judgments  a  priori,  were  originally  attained  by  the 
phyletic  development  of  the  judgment,  and  may  be 
reduced  to  constantly  repeated  experiences  and  a  priori 
conclusions  derived  therefrom.  The  "necessity"  which 
Kant  considered  to  be  a  special  feature  of  these  a  priori 
propositions  would  be  found  in  all  other  judgments  if  we 
were  fully  acquainted  with  the  phenomena  and  their  con- 
ditions. 

Among  the  censures  which  the  academic  metaphysi- 
cians, especially  in  Germany,  have  passed  on  my  Riddle  of 
the  Universe,  the  heaviest  is  perhaps  the  charge  that  I 
know  nothing  whatever  about  the  theory  of  knowledge. 
The  charge  is  correct  to  this  extent,  that  I  do  not  under- 
stand the  current  dualistic  theory  of  knowledge  which  is 
based  on  Kant's  metaphysics;  I  cannot  understand  how 
their  introspective  psychological  methods — disdaining 
all  physiological,  histological,  or  phylogenetic  founda- 
tions— can  satisfy  the  demands  of  "pure  reason."  My 
monistic  theory  of  knowledge  is  assuredly  very  different 
from  this.  It  is  firmly  and  thoroughly  based  on  the 
splendid  advances  of  modern  physiology,  histology,  and 
phylogeny — on  the  remarkable  results  of  these  empirical 
sciences  in  the  last  forty  years,  which  are  entirely 
ignored  by  the  prevailing  system  of  metaphysics.  It  is 
on  the  ground  of  these  experiences  that  I  have  adopted 
the  views  on  the  nature  of  the  human  mind  which  are  ex- 
pounded in  the  second  part  of  The  Riddle  of  the  Universe 
(chapters  vi.-xi.).     The  following  are  the  chief  points: 

II 


THE    WONDERS    OF    LIFE 

1.  The  soul  of  man  is — objectively  considered — essen- 
tially similar  to  that  of  all  other  vertebrates;  it  is  the 
physiological  action  or  function  of  the  brain. 

2.  Like  the  functions  of  all  other  organs,  those  of  the 
brain  are  effected  by  the  cells,  which  make  up  the 
organ. 

3.  These  brain-cells,  which  are  also  known  as  soul- 
cells,  ganglionic  cells,  or  neurona,  are  real  nucleated 
cells  of  a  very  elaborate  structure. 

4.  The  arrangement  and  grouping  of  these  psychic 
cells,  the  number  of  which  runs  into  millions  in  the 
brain  of  man  and  the  other  mammals,  is  strictly  regu- 
lated by  law,  and  is  distinguished  within  this  highest 
class  of  the  vertebrates  by  several  characteristics,  which 
can  only  be  explained  by  the  common  origin  of  the 
mammals  from  one  primitive  mammal  (or  pro-mammal 
of  the  Triassic  period). 

5.  Those  groups  of  psychic  cells  which  we  must  regard 
as  the  agents  of  the  higher  mental  functions  have  their 
origin  in  the  fore-brain,  the  earliest  and  foremost  of  the 
five  embryonic  brain-vesicles;  they  are  confined  to  that 
part  of  the  surface  of  the  fore-brain  which  anatomists 
call  the  cortex,  or  gray  bed,  of  the  brain. 

6.  Within  the  cortex  we  have  localized  a  number  of 
different  mental  activities,  or  traced  them  to  certain 
regions;  if  the  latter  are  destroyed,  their  functions  are 
extinguished. 

7.  These  regions  are  so  distributed  in  the  cortex  that 
one  part  of  them  is  directly  connected  with  the  organs  of 
sense,  and  receives  and  elaborates  the  impressions  from 
these:  these  are  the  inner  sense-centres,  or  sensoria. 

8.  Between  these  central  organs  of  sense  lie  the  intel- 
lectual or  thought-organs,  the  instruments  of  presenta- 
tion and  thought,  judgment  and  consciousness,  intellect 
and  reason;  they  are  called  the  thought-centres,  or 
association-centres,  because  the  various  impressions  re- 

13 


TRUTH 

ceived  from  the  sense-centres  are  associated,  combined, 
and  united  in  harmonious  thought  by  them.^ 

The  anatomic  distinction  between  the  two  regions  of 
the  cortex  which  we  oppose  to  each  other  as  the  internal 
sense-centres  and  the  thought  or  association-centres 
seems  to  me  of  the  highest  importance.  Certain  physio- 
logical considerations  had  for  some  time  suggested  this 
distinction,  but  the  sound  anatomic  proof  of  it  has  only 
been  furnished  during  the  last  ten  years.  In  1894 
Flechsig  showed  that  there  are  four  central  sense-regions 
("internal  sense-spheres,"  or  aestheta)  in  the  gray  cortex 
of  the  brain,  and  ^.our  thought-centres  ("association- 
centres,"  or  phroiieta)  between  these:  the  most  im- 
portant of  the  latter,  from  the  psychological  point  of 
view,  is  the  "principal  brain,"  or  the  "great  occipito- 
temporal association-centre."  The  anatomic  determina- 
tion of  the  two  "psychic  regions"  which  Flechsig  first 
introduced  was  afterwards  modified  by  himself  and  sub- 
stantially altered  by  others.  The  distinguished  works  of 
E dinger,  Weigert,  Hitzig,  and  others,  lead  to  somewhat 
discrepant  conclusions.  But  for  the  general  conception 
of  psychic  action,  and  especially  of  the  cognitive  func- 
tions, which  interests  us  at  present,  it  is  not  necessary 
to  have  this  delimitation  of  the  regions.  The  chief  point 
holds,  that  we  can  to-day  anatomically  distinguish  be- 
tween the  two  most  important  organs  of  mental  life; 
that  the  neurona,  which  compose  both,  differ  histolog- 
ically (or  in  finer  structure)  and  ontogenetically  (or 
in  origin) ;  and  that  even  chemical  differences  (or  a 
different  relation  to  certain  coloring  matters)  may  be 
perceived.  We  may  conclude  from  this  that  the 
neurona  or  psychic  cells  which  compose  both  organs  also 
differ  in  their  finer  structure;  there  is  probably  a  dif- 

^  Further  particulars  about  the  relations  of  the  thought- 
centres  to  the  sense-centres  will  be  found  in  the  tenth  chapter 
of  The  Riddle  of  the  Universe. 

13 


THE    WONDERS    OF    LIFE 

ference  in  the  complicated  fibrils  which  extend  in  the 
cytoplasm  of  both  organs,  although  our  coarse  means 
of  investigation  have  not  yet  succeeded  in  detecting 
this  difference.  In  order  to  distinguish  properly  be- 
tween the  two  sets  of  neurona,  I  propose  to  call  the 
sensory-cells  or  sense-centres  cFsthetal  cells,  and  the 
thought-cells  or  thought-centres  phronetal  cells.  The 
former  are,  anatomically  and  physiologically,  the  inter- 
mediaries between  the  external  sense-organs  and  the 
internal  thought-organs. 

To  this  anatomic  delimitation  of  the  internal  sense- 
centres  and  thought-organs  in  the  cortex  corresponds 
their  physiological  differentiation.  The  sensorium,  or 
sense-centre,  works  up  the  external  sense-impressions 
that  are  conveyed  by  the  peripheral  sense-organs  and  the 
specific  energy  of  their  sensory  nerves;  the  custheta,  or 
the  central  sense-instruments  that  make  up  the  sen- 
sorium, and  their  organic  units,  the  cesthetal  cells,  pre- 
pare the  sense-impressions  for  thought  and  judgment  in 
the  proper  sense.  This  work  of  "pure  reason "  is  accom- 
plished by  the  phronema  of  the  thought-centres,  the 
phroneta  (or  the  various  thought-organs  that  compose 
it)  and  their  histological  elements,  the  phronetal  cells, 
bringing  about  an  association  or  combination  of  the  pre- 
pared impressions.  By  this  important  distinction  we 
avoid  the  error  of  the  older  sensualism  (of  Hume, 
Condillac,  etc.) — namely,  that  all  knowledge  depends  on 
sense-action  alone  It  is  true  that  the  senses  are  the 
original  source  of  all  knowledge;  but,  in  order  to  have 
real  knowledge  and  thought,  the  specific  task  of  reason, 
the  impressions  received  from  the  external  world  by  the 
sense-organs,  and  their  nerves  and  centres,  must  be 
combined  in  the  association-centres  and  elaborated  in 
the  conscious  thought-centres.  Then  there  is_t.he  im- 
portant, but  frequently  overlooked,  circumstance  that 
there  is  in  advance  in  the  phronetal  cells  of  the  civilized 

14 


i"'W*"J*-^   -•■        -""" 


TRUTH 

man  a  valuable  quality  in  the  shape  of  inherited  potential 
nerve-energy,  which  was  originally  engendered  by  the 
actual  sense-action  of  the  aesthetal  cells  in  the  course  of 
many  generations. 

An  impartial  and  critical  study  of  the  action  of  the 
brain  in  various  scientific  leaders  shows  that,  as  a  rule, 
there  is  a  certain  opposition,  or  an  antagonistic  correla- 
tion, between  the  two  sections  of  the  highest  mental 
power.  The  empirical  representatives  of  science,  or 
those  who  are  devoted  to  physical  studies,  have  a  pre- 
ponderant development  of  the  sensorium,  which  means 
a  greater  disposition  and  capacity  for  the  observation  of 
phenomena  in  detail.  On  the  other  hand,  the  speculative 
representatives  of  what  is  called  mental  science  and 
philosophy,  or  of  metaphysical  studies,  have  the  phro- 
nema  more  strongly  developed,  which  means  a  pre- 
ponderant tendency  to,  and  capacity  for,  a  compre- 
hensive perception  of  the  universal  in  particulars.  Hence 
it  is  that  metaphysicians  usually  look  with  disdain  on 
"materialistic"  scientists  and  observers;  while  the  latter 
regard  the  play  of  ideas  of  the  former  as  an  unscien- 
tific and  speculative  dissipation.  This  physiological  an- 
tagonism may  be  traced  histologically  to  the  compara- 
tive development  of  the  assthetal  and  the  phronetal 
cells  in  the  two  cases.  It  is  only  in  natural  philosophers 
of  the  first  rank,  such  as  Copernicus,  Newton,  Lamarck, 
Darwin,  and  Johannes  Miiller,  that  both  sections  are 
harmoniously  developed,  and  thus  the  individual  is 
equipped  for  the  highest  mental  achievements. 

If  we  take  the  ambiguous  term  "soul"  {psyche  or 
anima)  in  the  narrower  sense  of  the  higher  mental 
power,  we  may  assign  as  its  "seat"  (or,  more  correctly, 
its  organ),  in  man  and  the  other  mammals,  that  part  of 
the  cortex  which  contains  the  phroneta  and  is  made  up 
of  the  phronetal  cells;  a  short  and  convenient  name  for 
this  is  the  phronerna.     According  to  our  monistic  theory, 

15 


THE    WONDERS    OF    LIFE 

the  phronema  is  the  organ  of  thought  in  the  same  sense 
in  which  we  consider  the  eye  the  organ  of  vision,  or  the 
heart  the  central  organ  of  circulation.  With  the  destruc- 
tion of  the  organ  its  function  disappears.  In  opposition 
to  this  biological  and  empirically  grounded  theory,  the 
current  metaphysical  psychology  regards  the  brain  as 
the  seat  of  the  soul,  only  in  a  very  different  sense.  It 
has  a  strictly  dualistic  conception  of  the  human  soul  as 
a  being  apart,  only  dwelling  in  the  brain  (like  a  snail  in 
its  shell)  for  a  time.  At  the  death  of  the  brain  it  is 
supposed  to  live  on,  and  indeed  for  all  eternity.  The 
immortal  soul,  on  this  theory  (which  we  can  trace  to 
Plato),  is  an  immaterial  entity,  feeling,  thinking,  and 
acting  independently,  and  only  using  the  material  body 
as  a  temporary  implement.  The  well-known  "piano- 
theory"  compares  the  soul  to  a  musician  who  plays  an 
interesting  piece  (the  individual  life)  on  the  instrument 
of  the  body,  and  then  deserts  it,  to  live  forever  on  its 
own  account.  According  to  Descartes,  who  insured  the 
widest  acceptance  for  Plato's  dualistic  mysticism,  the 
proper  habitation  of  the  soul  in  the  brain — in  the  music- 
room — is  the  pineal  gland,  a  posterior  section  of  the 
middle-brain  (the  second  embryonic  cerebral  vesicle). 
The  famous  pineal  gland  has  lately  been  recognized  by 
comparative  anatomists  as  the  rudiment  of  a  single  organ 
of  vision,  the  pineal  eye  (which  is  still  found  in  certain 
reptiles).  Moreover,  not  one  of  the  innumerable  psychol- 
ogists w^ho  seek  the  seat  of  the  soul  in  some  part  of  the 
body,  after  the  fashion  of  Plato,  has  yet  formulated  a 
plausible  theory  of  the  connection  of  mind  and  body  and 
the  nature  of  their  reciprocal  action.  On  our  monistic 
principles  the  answer  to  this  question  is  very  simple, 
and  consonant  with  experience.  In  view  of  its  extreme 
importance,  it  is  advisable  to  devote  at  least  a  few  lines 
to  the  consideration  of  the  phronema  in  the  light  of 
anatomy,  physiology,  ontogeny,  and  phylogeny. 

i6 


TRUTH 

When  we  conceive  the  phronema  as  the  real  "organ 
of  the  soul"  in  the  strict  sense — that  is  to  say,  as  the 
central  instrument  of  thought,  knowledge,  reason,  and 
consciousness — we  may  at  once  lay  down  the  principle 
that  there  is  an  anatomical  unity  of  organ  corresponding 
to  the  physiological  and  generally  admitted  unity  of 
thought  and  consciousness.  As  we  assign  to  this 
phronema  a  most  elaborate  anatomical  structure,  we 
may  call  it  the  organic  apparatus  of  the  soul,  in  the 
same  sense  in  which  we  conceive  the  eye  as  a  pur- 
posively  arranged  apparatus  of  vision.  It  is  true  that 
we  have  as  yet  only  made  a  beginning  of  the  finer 
anatomic  analysis  of  the  phronema,  and  are  not  yet  able 
to  mark  off  its  field  decisively  from  the  neighboring 
spheres  of  sense  and  motion.  With  the  most  improved 
means  of  modern  histology,  the  most  perfect  microscopes 
and  coloring  methods,  we  are  only  just  beginning  to 
penetrate  into  the  marvellous  structure  of  the  phronetal 
cells  and  their  complicated  grouping.  Yet  we  have 
advanced  far  enough  to  regard  it  as  the  most  perfect 
piece  of  cell-machinery  and  the  highest  product  of 
organic  evolution.  Millions  of  highly  differentiated 
phronetal  cells  form  the  several  stations  of  this  tele- 
graphic system,  and  thousands  of  millions  of  the  finest 
nerve-fibrils  represent  the  wires  which  connect  the 
stations  with  one  another  and  with  the  sense-centres  on 
the  one  hand,  and  with  the  motor-centres  on  the  other. 
Comparative  anatomy,  moreover,  acquaints  us  with  the 
long  and  gradual  development  which  the  phronema  has 
undergone  within  the  higher  class  of  the  vertebrates, 
from  the  amphibia  and  reptiles  up  to  the  birds  and 
mammals,  and,  within  the  last  class,  from  the  mono- 
tremes  and  marsupials  up  to  the  apes  and  men.  The 
human  brain  seems  to  us  to-day  to  be  the  greatest 
marvel  that  plasm,  or  the  "living  substance,"  has  pro- 
duced in  the  course  of  millions  of  years. 

17 


THE    WONDERS    OF    LIFE 

The  remarkable  progress  which  has  been  made  in  the 
last  few  decades  in  the  anatomic  and  histological  investi- 
gation of  the  brain  does  not  yet,  it  is  true,  enable  us  to 
make  a  clear  delimitation  of  the  region  of  the  phronema 
and  its  relations  to  the  neighboring  sensory  and  motor 
spheres  in  the  cortex.  We  must,  in  fact,  assume  that 
there  is  no  sharp  distinction  in  the  lower  stages  of  the 
vertebrate  soul;  in  the  older  and  phylogenetically  more 
distant  stages  they  were  not  yet  differentiated.  Even 
now  there  are  still  intermediaries  between  the  aesthetal 
and  phronetal  cells.  But  we  may  expect  with  confidence 
that  further  progress  in  the  comparative  anatomy  of  the 
brain  will,  with  the  aid  of  embryology,  throw  more  and 
more  light  on  these  complicated  structures.  In  any  case, 
the  fundamental  fact  is  now  empirically  established  that 
the  phronema  (the  real  organ  of  the  soul)  forms  a 
definite  part  of  the  cortex  of  the  brain,  and  that  without 
it  there  can  be  no  reason,  no  mental  life,  no  thought, 
and  no  knowledge. 

Since  we  regard  psychology  as  a  branch  of  physiology, 
anH'examine  the  whole  of  the  phenomena  of  mental  life 
from  the  same  monistic  stand-point  as  all  other  vital 
functions,  it  follows  that  we  can  make  no  exception  for 
knowledge  and  reason.  In  this  we  are  diametrically 
opposed  to  the  current  systems  of  psychology,  which 
regard  psychology,  not  as  a  natural  science,  but  as  a 
mental  science.  In  the  next  chapter  we  shall  see  that 
this  position  is  wholly  unjustified.  Unfortunately,  this 
dualistic  attitude  is  shared  by  a  number  of  distinguish- 
ed modern  physiologists,  who  otherwise  adopt  the 
monistic  principles;  they  take  the  soul  to  be,  in  the 
Cartesian  sense,  a  supernatural  entity.  Descartes — a 
pupil  of  the  Jesuits — only  applied  his  theory  to  man, 
and  regarded  animals  as  soulless  automata.  But  the 
theory  is  quite  absurd  in  modern  physiologists,  who 
know  from  innumerable  observations   and  experiments 

i8 


TRUTH 

that  the  brain,  or  psychic  organ,  in  man  behaves  just 
as  it  does  in  the  other  mammals,  and  especially  the 
primates.  This  paradoxical  dualism  of  some  of  our 
modern  physiologists  may  be  partly  explained  by  the 
perverse  theory  of  knowledge  which  the  great  authority 
of  Kant,  Hegel,  etc.,  has  imposed  on  them;  and  partly 
by  a  concern  for  the  current  belief  in  immortality,  and 
the  dread  of  being  decried  as  "materialists"  if  they 
abandon  it.  As  I  do  not  share  this  beUef ,  I  examine  and 
appreciate  the  physiological  work  of  the  phroneta  just  as 
impartially  as  I  deal  with  the  organs  of  sense  or  the 
muscles.  I  find  that  the  one  is  just  as  much  subject  as 
the  other  to  the  law  of  substance.  Hence  we  must  re- 
gard the  chemical  processes  in  the  ganglionic  cells  of  the 
cortex  as  the  real  factors  of  knowledge  and  all  other 
psychic  action.  The  chemistry  of  the  neuroplasm  de- 
termines the  vital  function  of  the  phronema.  The  same 
must  be  said  of  its  most  perfect  and  enigmatic  function, 
consciousness.  Although  this  greatest  wonder  of  life 
is  only  directly  accessible  by  the  introspective  method, 
or  by  the  mirroring  of  knowledge  in  knowledge,  never- 
theless the  use  of  the  comparative  method  in  psychology 
leads  us  to  believe  confidently  that  the  lofty  self- 
consciousness  of  man  differs  only  in  degree,  and  not  in 
kind,  from  that  of  the  ape,  dog,  horse,  and  other  higher 
mammals. 

Our  monistic  conception  of  the  nature  and  seat  of  the 
soul  is  strongly  confirmed  by  psychiatry,  or  the  science 
of  mental  disease.  As  an  old  medical  maxim  runs, 
Patkologia  physiologiani  illustrat — the  science  of  disease 
throws  light  on  the  sound  organism.  This  maxim  is 
especially  applicable  to  mental  diseases,  for  they  can  all 
be  traced  to  modifications  of  parts  of  the  brain  which 
discharge  definite  functions  in  the  normal  state.  The 
localization  of  the  disease  in  a  definite  part  of  the 
phronema  diminishes  or  extinguishes  the  normal  mental 

19 


THE    WONDERS    OF    LIFE 

ftmction  which  is  discharged  by  this  section.  Thus 
disease  of  the  speech-centre,  in  the  third  frontal  convolu- 
tion, destroys  the  power  of  speech;  the  destruction  of 
the  visual  region  (in  the  occipital  convolutions)  does 
away  with  the  power  of  sight ;  the  lesion  of  the  temporal 
convolutions  destroys  hearing.  Nature  herself  here  con- 
ducts delicate  experiments  which  the  physiologist  could 
only  accomplish  very  imperfectly  or  not  at  all.  And  al- 
though we  have  in  this  way  only  succeeded  as  yet  in 
showing  the  functional  dependence  of  a  certain  part  of  the 
mental  functions  on  the  respective  parts  of  the  cerebrum, 
no  unprejudiced  physician  doubts  to-day  that  it  is 
equally  true  of  the  other  parts.  Each  special  mental 
activity  is  determined  by  the  normal  constitution  of  the 
relevant  part  of  the  brain,  a  section  of  the  phronema. 
Very  striking  examples  of  this  are  afforded  in  the  case 
of  idiots  and  microcephali,  the  unfortunate  beings  whose 
cerebrum  is  more  or  less  stunted,  and  who  have  accord- 
ingly to  remain  throughout  life  at  a  low  stage  of  mental 
capacity.  These  poor  creatures  would  be  in  a  very 
pitiable  condition  if  they  had  a  clear  consciousness  of  it, 
but  that  is  not  the  case.  They  are  like  vertebrates 
from  which  the  cerebrum  has  been  partly  or  wholly 
removed  in  the  laboratory.  These  may  live  for  a  long 
time,  be  artificially  fed,  and  execute  automatic  or 
reflex  (and  in  part  purposive)  motions,  without  our 
perceiving  a  trace  of  consciousness,  reason,  or  other 
mental  function  in  them. 

The  embryology  of  the  child-soul  has  been  known  in  a 
general  way  for  thousands  of  years,  and  has  been  an 
object  of  keen  interest  to  all  observant  parents  and 
teachers;  but  it  was  not  until  about  twenty  years  ago 
that  a  strictly  scientific  study  was  made  of  this  remark- 
able and  important  phenomenon.  In  1884  Kussmaul 
published  his  Untersuchungen  iiber  das  Seelenleben  des 
neugeborenen  Menschcn,  and  in   1882  W.   Preyer  pub- 

20 


TRUTH 

lished  his  Mind  of  the  Child  [English  translation;  Dr.  J. 
Sully  has  several  works  on  the  same  subject].  From  the 
careful  manuals  which  these  and  other  observers  have 
published,  it  is  clear  that  the  new-born  infant  not  only 
has  no  reason  or  consciousness,  but  is  also  deaf,  and  only 
gradually  develops  its  sense  and  thought-centres.  It  is 
only  by  gradual  contact  with  the  outer  world  that  these 
functions  successively  appear,  such  as  speech,  laughing, 
etc.;  later  still  come  the  power  of  association,  the  form- 
ing of  concepts  and  words,  etc.  Recent  anatomic  ob- 
servations quite  accord  with  these  physiological  facts. 
Taken  together,  they  convince  us  that  the  phronema  is 
undeveloped  in  the  new-born  infant;  and  so  we  can  no 
more  speak  in  this  case  of  a  "seat  of  the  soul"  than  of 
a  "human  spirit"  as  a  centre  of  thought,  knowledge,  and 
consciousness.  Hence  the  destruction  of  abnormal  new- 
born infants — as  the  Spartans  practised  it,  for  instance, 
in  selecting  the  bravest — cannot  rationally  be  classed  as 
"murder,"  as  is  done  in  even  modern  legal  works.  We 
ought  rather  to  look  upon  it  as  a  practice  of  advantage 
both  to  the  infants  destroyed  and  to  the  community. 
As  the  whole  course  of  embryology  is,  according  to  our 
biogenetic  law,  an  abbreviated  repetition  of  the  history 
of  the  race,  we  must  say  the  same  of  psychogenesis,  or 
the  development  of  the  "soul"  and  its  organ — the 
phronema. 

Comparative  psychology  comes  next  in  importance  to 
embryology  as  a  means  of  studying  the  ancestral  history 
of  the  soul.  Within  the  ranks  of  the  vertebrates  we 
find  to-day  a  long  series  of  evolutionary  stages  which 
reach  up  from  the  lowest  acrania  and  cyclostoma  to 
the  fishes  and  dipneusta,  from  these  to  the  amphibia, 
and  from  these  again  to  the  amniota.  Among  the 
latter,  moreover,  the  various  orders  of  reptiles  and  birds 
on  the  one  hand,  and  of  mammals  on  the  other,  show 
us  how  the  higher  psychic  powers  have  been  developed 

21 


THE    WONDERS    OF    LIFE 

step  by  step  from  the  lower.  To  this  physiological 
scale  corresponds  exactly  the  morphological  gradation 
revealed  by  the  comparative  anatomy  of  the  brain. 
The  most  interesting  and  important  part  of  this  is  that 
which  relates  to  the  highest  developed  class  —  the 
mammals;  within  this  class  we  find  the  same  ever- 
advancing  gradation.  At  its  summit  are  the  primates 
(man,  the  apes,  and  the  half -apes),  then  the  carnivora,  a 
part  of  the  ungulates,  and  the  other  placentals.  A  wide 
interval  seems  to  separate  these  intelligent  mammals 
from  the  lower  placentals,  the  marsupials  and  mono- 
tremes.  We  do  not  find  in  the  latter  the  high  quantita- 
tive and  qualitative  development  of  the  phronema  which 
we  have  in  the  former;  yet  we  find  every  intermediate 
stage  between  the  two.  The  gradual  development  of  the 
cerebrum  and  its  chief  part — the  phronema — took  place 
during  the  Tertiary  period,  the  duration  of  which  is 
estimated  by  many  recent  geologists  at  from  twelve  to 
fifteen  (at  the  least  three  to  five)  million  years. 

As  I  have  gone  somewhat  fully,  in  chapters  vi.-ix.  of 
the  Riddle,  into  the  chief  results  of  the  modern  study  of 
the  brain  and  its  radical  importance  for  psychology  and 
the  theory  of  knowledge,  I  need  only  refer  the  reader 
thereto.  There  is  just  one  point  I  may  touch  here,  as 
it  has  been  attacked  with  particular  vehemence  by  my 
critics.  I  had  made  several  allusions  to  the  works  of 
the  distinguished  English  zoologist,  Romanes,  who  had 
made  a  careful  comparative  study  of  mental  develop- 
ment in  the  animal  and  man,  and  had  continued  the 
work  of  Darwin.  Romanes  partly  retracted  his  monis- 
tic convictions  shortly  before  his  death,  and  adopted 
mystic  religious  views.  As  this  conversion  was  only 
known  at  first  through  one  of  his  friends,  a  zealous  Eng- 
lish theologian  [Dr.  Gore],  it  was  natural  to  retain  a 
certain  reserve.  However,  it  turned  out  that  there  had 
really  been  in  this  case  (just  as  in  the  case  of  the  aged 

22 


TRUTH 

Baer)  one  of  those  interesting  psychological  metamor- 
phoses which  I  have  described  in  chapter  vi.  of  the 
Riddle.  Romanes  suffered  a  good  deal  from  illness  and 
grief  at  the  loss  of  friends  in  his  last  years.  In  this  con- 
dition of  extreme  depression  and  melancholy  he  fell  un- 
der mystic  influences  which  promised  him  rest  and  hope 
by  belief  in  the  supernatural.  It  is  hardly  necessary  to 
point  out  to  impartial  readers  that  such  a  conversion  as 
this  does  not  shake  his  earlier  monistic  views.  As  in 
similar  cases  where  deep  emotional  disturbance,  painful 
experiences,  and  exuberant  hope  have  clouded  the 
judgment,  we  must  still  hold  that  it  is  the  place  of  the 
latter,  and  not  of  the  emotions  or  of  any  supernatural 
revelation,  to  attain  a  knowledge  of  the  truth.  But  for 
such  attainment  it  is  necessary  for  the  organ  of  mind, 
the  phronema,  to  be  in  a  normal  condition.' 

Of  all  the  wonders  of  life,  consciousness  may  be  said 
to  be  the  greatest  and  most  astounding.  It  is  true  that 
to-day  most  physiologists  are  agreed  that  man's  con- 
sciousness, like  all  his  other  mental  powers,  is  a  function 
of  the  brain,  and  may  be  reduced  to  physical  and 
chemical  processes  in  the  cells  of  the  cortex.  Neverthe- 
less, some  biologists  still  cling  to  the  metaphysical  view 
that  this  "central  mystery  of  psychology"  is  an  in- 
soluble enigma,  and  not  a  natural  phenomenon.  In  face 
of  this,  I  must  refer  the  reader  to  the  monistic  theory 
of  consciousness  which  I  have  given  in  chapter  x.  of  the 
Riddle,  and  must  insist  that  in  this  case  again  embryol- 
ogy is  the  best  guide  to  a  comprehension  of  the  subject. 
Sight  is  next  to  consciousness,  in  many  respects,  as  one 
of  the  wonders  of  life.  The  well-known  embryology  of 
the  eye  teaches  us  how  sight — the  perception  of  images 

'  English  readers  who  are  acquainted  with  Romanes's  post- 
humous Thoughts  on  Religion  will  recognize  the  justice  of  this 
analysis.  Romanes  speaks  expressly  of  the  acceptance  of 
Christianity  entailing  "the  sacrifice  of  his  intellect." — Trans. 

23 


THE    WONDERS    OF    LIFE 

from  the  external  world — has  been  gradually  evolved 
from  the  simple  sensitiveness  to  light  of  the  lower 
animals,  by  the  development  of  a  transparent  lens.  In 
the  same  way  the  conscious  soul,  the  internal  mirror  of 
the  mind's  own  action,  has  been  produced  as  a  new 
wonder  of  life  out  of  the  unconscious  associations  in 
the  phronema  of  our  earher  vertebrate  ancestors. 

From  this  thorough  and  unprejudiced  appreciation  of 
the  biology  of  the  phronema  it  follows  that  the  knowl- 
edge of  truth,  the  aim  of  all  science,  is  a  natural  physio- 
logical process,  and  that  it  must  have  its  organs  like 
all  other  psychic  functions.  These  organs  have  been 
revealed  to  us  so  fully  in  the  advance  of  biology  during 
the  last  half-century  that  we  may  be  said  to  have  a 
generally  satisfactory  idea  of  the  natural  character  of 
their  organization  and  action,  though  we  are  still  far 
from  enjoying  a  complete  anatomical  and  physiological 
insight  into  their  details.  The  most  important  acquisi- 
tion we  have  made  is  the  conviction  that  all  knowledge 
was  originally  acquired  a  posteriori  and  from  experience, 
and  that  its  first  sources  are  the  impressions  made  on 
our  organs  of  sense.  Both  these — the  peripheral  sense- 
organs — and  the  phronema,  or  central  psychic  organ, 
are  subject  to  the  law  of  substance;  and  the  action  of 
the  phronema  is  just  as  reducible  to  chemical  and 
physical  processes  as  the  action  of  the  organs  of  sense. 

In  diamietrical  opposition  to  our  monistic  and  em- 
pirical theory  of  knowledge,  the  prevailing  dualistic 
metaphysics  assumes  that  our  knowledge  is  only  partly 
empirical  and  a  posteriori,  and  is  partly  quite  indepen- 
dent of  experience  and  a  priori,  or  due  to  the  original  con- 
stitution of  our  "immaterial"  mind.  The  powerful  au- 
thority of  Kant  has  lent  enormous  prestige  to  this  mystic 
and  supernatural  view,  and  the  academic  philosophers 
of  our  time  are  endeavoring  to  maintain  it.  A  "return 
to  Kant"  is  held  to  be  the  only  means  of  salvation  for 

24 


TRUTH 

philosophy ;  in  my  opinion  it  should  be  a  return  to  nat- 
ure. As  a  fact,  the  return  to  Kant  and  his  famous 
theory  of  knowledge  is  an  unfortunate  "crab-walk"  on 
the  part  of  philosophy.  Our  modern  metaphysicians 
regard  the  brain,  as  Kant  did  one  hundred  and  twenty 
years  ago,  as  a  mysterious,  whitish-gray,  pulpy  mass, 
the  significance  of  which  as  an  instrument  of  the  mind 
is  very  enigmatic  and  obscure.  But  for  modern  biology 
the  brain  is  the  most  wonderful  structure  in  nature,  a 
compound  of  innumerable  soul-cells  or  neurona.  These 
have  a  most  elaborate  finer  structure,  are  combined  in  a 
vast  psychic  apparatus  by  thousands  of  interlacing  nerve- 
fibrils,  and  are  thus  fitted  to  accomplish  the  highest  men- 
tal functions. 

First  Table 

ANTITHESIS   OF   THE   TWO   WAYS  OF  ATTAINING 

THE    TRUTH 


Monistic  Theory  of  Knowl- 
edge 

1 .  Knowledge  is  a  n atural  proc- 

ess, not  a  miracle. 

2.  Knowledge,    as     a     natural 

process,  is  subject  to  the 
general  law  of  substance. 

3.  Knowledge  is  a  physiological 

process,  with  the  brain  for 
its  anatomic  organ. 

4.  The  part  of  the  human  brain 

in  which  knowledge  is 
exclusively  engendered 
is  a  definite  and  limited 
part  of  the  cortex,  the 
phronema. 

5.  The  organ  of  knowledge,  or 

the  phronema,  consists  of 
the  association  -  centres, 
and  differs  by  its  special 
histological  structure  from 
the  neighboring  sensory 
and  motor  centres  in  the 
cortex,  and  it  is  in  close 
relation  with  these. 


DuALiSTic  Theory  of  Knowl- 
edge 

1.  Knowledge  is  a  supernatural 

process,  a  miracle. 

2.  Knowledge,    as   a   transcen- 

dental process,  is  not  sub- 
ject to  the  law  of  sub- 
stance. 

3.  Knowledge  is  not  a  physio- 

logical, but  a  purely  spirit- 
ual, process. 

4.  The  part  of  the  human  brain 

which  seems  to  act  as 
organ  of  knowledge  is 
really  only  the  instrument 
that  allows  the  spiritual 
process  to  appear. 

5.  The  organ  of  knowledge,  or 

the  phronema  (the  sum  of 
the  association  -  centres), 
is  merely  a  part  of  the 
instrument  of  mind,  like 
the  neighboring  and  corre- 
lated sensory  and  motor- 
centres. 


25 


to:  M.  HILL  LIBRARY 


THE    WONDERS    OP    LIFE 


ANTITHESIS  OF  THE  TWO   WAYS  OF  ATTAINING 

THE   TR\JTU~Continued 


6.  The  innumerable  cells  which 

make  up  the  phronema — 
the  phronetal  cells — are 
the  elementary  organs  of 
the  cognitive  process:  the 
possibility  of  knowledge 
depends  on  their  normal 
physical  texture  and  chem- 
ical composition. 

7.  The     phj^sical     process     of 

knowledge  consists  in  the 
combination  or  associa- 
tion of  presentations,  the 
first  sources  of  which  are 
the  impressions  transmit- 
ted to  the  sense-centres. 

8.  Hence   all    knowledge    orig- 

inally comes  from  ex- 
perience, by  means  of  the 
organs  of  sense;  partly 
directly  (direct  experi- 
ence, observation,  and  ex- 
periment of  the  present), 
partly  indirectly  (histor- 
ical and  indirectly  trans- 
mitted past  experiences). 
All  knowledge  (even  math- 
ematical) is  of  empirical 
origin  and  a  posteriori. 


The  innumerable  phronetal 
cells,  as  the  microscopic 
elementary  parts  of  the 
phronema,  are,  it  is  true, 
indispensable  instruments 
of  the  cognitive  process, 
but  not  its  real  factors — 
merely  finer  parts  of  its 
instrument. 

The  metaphysical  process  of 
knowledge  consists  in  the 
combination  or  association 
of  presentations,  which  are 
only  partly  traceable  to 
sense-impressions,  and  are 
partly  supersensual,  tran- 
scendental processes. 

Hence  knowledge  is  of  two 
kinds:  empirical  and  a 
posteriori  knowledge,  ob- 
tained by  experience,  and 
transcendental  a  priori 
knowledge,  independent  of 
experience.  Mathematics 
especially  belongs  to  the 
latter  class,  its  axioms 
differing  from  empirical 
truths  by  their  absolute 
certainty. 


II 

LIFE 

Definition  of  life — Comparison  with  a  flame — Organism  and 
organization — Machine  theory  of  Hfe — Organisms  without 
organs:  monera — Organization  and  hfe  of  the  chromacea — 
Stages  of  organization — Complex  organisms — Symbolic 
organisms — Organic  compounds — Organisms  and  inorganic 
bodies  compared  in  regard  to  matter,  form,  and  function — • 
Crystalloid  and  colloid  substances — Life  of  crystals — 
Growth  of  crystals — Waves  of  growth — Metabolism — 
Catalysis  —  Fermentation  —  Biogenesis  —  Vital  force  —  Old 
and  new  vitalism  —  Palavitalism  —  Anti  vitalism  —  Neo- 
vitalism. 

AS  the  object  of  this  work  is  the  critical  study  of  the 
i.  wonders  of  life,  and  a  knowledge  of  the  truth  con- 
cerning them,  we  must  first  of  all  form  a  clear  idea  of  the 
meaning  of  "life"  and  "wonder,"  or  miracle.  For 
thousands  of  years  men  have  appreciated  the  difference 
between  life  and  death,  between  living  and  lifeless  bodies ; 
the  former  are  called  organisms,  and  the  latter  known  as 
inorganic  bodies.  Biology — in  the  widest  sense — is  the 
name  of  the  science  which  treats  of  organisms ;  we  might 
call  the  science  which  deals  with  the  inorganic  "abi- 
ology,"  abiotik,  or  anorgik.  The  chief  difference  be- 
tween the  two  provinces  is  that  organisms  accomplish 
peculiar,  periodically  repeated,  and  apparently  spon- 
taneous movements,  which  we  do  not  find  in  inorganic 
matter.  Hence  life  may  be  conceived  as  a  special 
process  of  movement.  Recent  study  has  shown  that 
this  is   always   connected  with  a   particular   chemical 

27 


THE    WONDERS    OF    LIFE 

substance,  plasm,  and  consists  essentially  in  a  circula- 
tion of  matter,  or  metabolism.  At  the  same  time 
modern  science  has  shown  that  the  sharp  distinction 
formerly  drawn  between  the  organic  and  the  inorganic 
cannot  be  sustained,  but  that  the  two  kingdoms  are 
profoundly  and  inseparably  united. 

Of  all  the  phenomena  of  inorganic  nature  with  which 
the  life-process  may  be  compared,  none  is  so  much  like 
it  externally  and  internally  as  the  flame.  This  important 
comparison  was  made  two  thousand  four  hundred  years 
ago  by  one  of  the  greatest  philosophers  of  the  Ionic 
school,  Heraclitus  of  Ephesus — the  same  thinker  who 
first  broached  the  idea  of  evolution  in  the  two  words, 
Panta  rei — all  things  are  in  a  state  of  flux.  Heracli- 
tus shrewdly  conceived  life  as  a  fire,  a  real  process  of 
combustion,  and  so  compared  the  organism  to  a  torch. 

Max  Verworn  has  lately  employed  this  metaphor 
with  great  effect  in  his  admirable  work  on  general 
physiology,  and  has  especially  dealt  with  the  comparison 
of  the  individual  life-form  with  the  familiar  butterfly 
shape  of  the  gas-flame.     He  says: 

The  comparison  of  life  to  a  flame  is  particulariy  smtable  for 
helping  us  to  realize  the  relation  between  form  and  metabolism. 
The  butterfly-shape  of  a  gas-flame  has  a  very  characteristic 
outline.  At  the  base,  immediately  above  the  burner,  there 
is  still  complete  darkness;  over  this  is  a  blue  and  faintly  lumi- 
nous zone;  and  over  this  again  the  bright  flame  expands  on  either 
side  like  the  wings  of  a  butterfly.  This  peculiar  form  of  the 
flame,  with  its  characteristic  features,  which  are  permanent,  as 
long  as  we  do  not  interfere  with  the  gas  or  the  environment,  is 
solely  due  to  the  fact  that  the  grouping  of  the  molecules  of  the 
gas  and  the  oxygen  at  various  parts  of  the  flame  is  constant, 
though  the  molecules  themselves  change  every  moment.  At 
the  base  of  the  flame  the  molecules  of  the  gas  are  so  thickly 
pressed  that  the  oxygen  necessary  for  their  combustion  cannot 
penetrate;  hence  the  darkness  we  find  here.  In  the  bluish  zone 
a  few  molecules  of  oxygen  have  combined  with  the  molecules 
of  the  gas:  we  have  a  faint  light  as  the  result.     But  in  the 

28 


LIFE 

body  of  the  flame  the  molecules  of  the  gas  are  so  freely  com- 
bined with  the  oxygen  of  the  atmosphere  that  we  have  a  lively 
combustion.  However,  the  exchange  of  matter  (metabolism) 
between  the  outpouring  gas  and  the  surrounding  air  is  so  reg- 
ulated that  we  always  find  the  same  molecules  in  the  same 
quantity  at  the  same  spot.  Thus  we  get  the  permanent  flame, 
with  all  its  characteristics.  But  if  we  alter  the  circulation  by 
lessening  the  stream  of  gas,  the  shape  of  the  flame  changes, 
because  now  the  disposition  of  the  molecules  on  both  sides  is 
different.  Thus  the  study  of  the  gas-jet  gives  us,  even  in  detail, 
the  features  we  find  in  the  structure  of  the  cell. 

The  scientific  soundness  of  this  metaphor  is  all  the  more 
notable  as  the  phrase,  "the  flame  of  life,"  has  long  been 
familiar  both  in  poetry  and  popular  parlance. 

In  the  sense  in  which  science  usually  employs  the 
word  "organism,"  and  in  which  we  employ  it  here,  it  is 
equivalent  to  "living  thing"  or  "living  body."  The 
opposite  to  it,  in  the  broad  sense,  is  the  anorganic  or 
inorganic  body.  Hence  he  word  "organism"  belongs 
to  physiology,  and  connotes  essentially  the  visible  life- 
activity  of  the  body,  its  metabolism,  nutrition,  and 
reproduction. 

However,  in  most  organisms  we  find,  when  we  ex- 
amine their  structure  closely,  that  this  consists  of  va- 
rious parts,  and  that  these  parts  are  put  together  for  the 
evident  purpose  of  accomplishing  the  vital  functions. 
We  call  them  organs,  and  the  manner  in  which  they  are 
combined,  apparently  on  a  definite  plan,  is  their  or- 
ganization. In  this  respect,  we  compare  the  organism 
to  a  machine  in  which  some  one  has  similarly  combined 
a  number  of  (lifeless)  parts  for  a  definite  purpose,  but 
according  to  a  preconceived  and  rationally  initiated 
design. 

The  familiar  comparison  of  an  organism  to  a  machine 
has  given  rise  to  very  serious  errors  in  regard  to  the 
former,  and  has,  of  late,  been  made  the  base  of  false 
duaHstic  principles.     The  modern  "machine-theory  of 

29 


THE    WONDERS    OF    LIFE 

life"  which  is  raised  thereon  demands  an  inteUigent 
design  and  a  deliberate  constructing  engineer  for  the 
origin  of  the  organism,  just  as  we  find  in  the  case  of  the 
machine.  The  organism  is  then  very  freely  compared 
to  a  watch  or  a  locomotive.  In  order  to  secure  the 
regular  working  of  such  a  complicated  mechanism,  it  is 
necessary  to  arrange  for  a  perfect  co-operation  of  all  its 
parts,  and  the  slightest  accident  to  a  single  wheel  suffices 
to  throw  it  out  of  gear.  This  figure  was  particularly 
employed  by  Louis  Agassiz  (1858),  who  saw  "an  incar- 
nate thought  of  the  Creator"  in  every  species  of  animal 
and  plant.  Of  late  years  it  has  been  much  used  by 
Reinke  in  the  support  of  his  theosophic  dualism.  He 
described  God,  or  "the  world-soul,"  as  the  "cosmic  in- 
telligence," but  ascribes  to  this  mystic  immaterial  being 
the  same  attributes  that  the  catechism  and  the  preacher 
give  to  the  Creator  of  heaven  and  earth.  He  compares 
the  human  intelligence  which  the  watch-maker  has 
put  into  the  elaborate  structure  of  the  watch  with  the 
"cosmic  intelligence"  which  the  Creator  has  put  in 
the  organism,  and  insists  that  it  is  impossible  to  deduce 
its  purposive  organization  from  its  material  constituents. 
In  this  he  entirely  overlooks  the  immense  difTerence 
between  the  "raw  material"  in  the  two  cases.  The 
"organs"  of  the  watch  are  metallic  parts,  which  fulfil 
their  purpose  in  virtue  only  of  their  physical  properties 
f^ha-rdness,  elasticity,  etc.).  The  organs  of  the  living 
organism,  on  the  other  hand,  perform  their  functions 
chiefly  in  virtue  of  their  chemical  composition.  Their 
soft  plasma-body  is  a  chemical  laboratory,  the  highly 
elaborate  molecular  structure  of  which  is  the  historical 
product  of  countless  complicated  processes  of  heredity 
and  adaptation.  This  invisible  and  hypothetical  molec- 
ular structure  must  not  (as  is  often  done)  be  confused 
with  the  real  and  microscopically  discoverable  structure 
of  the  plasm,  which  is  of  great  importance  in  the  question 

30 


LIFE 

of  organization.  If  one  is  disposed  to  assume  for  this 
molecular  structure  a  simple  chemical  substance,  a 
deliberate  design,  and  an  "  intelligent  natural  force"  for 
cause,  one  is  bound  to  do  the  same  for  powder,  and  say 
that  the  molecules  of  charcoal,  sulphur,  and  saltpetre 
have  been  purposively  combined  to  produce  an  ex- 
plosion. It  is  well  known  that  powder  was  not  made 
according  to  a  theory,  but  accidentally  discovered  in 
the  course  of  experiment.  The  whole  of  this  favorite 
machine-theory  of  life,  and  the  far-reaching  dualistic 
conclusions  drawn  from  it,  tumble  to  pieces  when  we 
study  the  simplest  organisms  known  to  us,  the  monera; 
for  these  are  really  organisms  without  organs — and 
without  organization ! 

I  endeavored  in  my  Gcnerelle  Morphologic  (1866)  to 
draw  the  attention  of  biologists  to  these  simplest  and 
lowest  organisms  which  have  no  visible  organization  or 
composition  from  different  organs.  I  therefore  proposed 
to  give  them  the  general  title  of  monera.  The  more  I 
have  studied  these  structureless  beings — cells  without 
nuclei! — since  that  time,  the  more  I  have  felt  their 
importance  in  solving  the  greatest  questions  of  biology — 
the  problem  of  the  origin  of  life,  the  nature  of  life,  and 
so  on.  Unfortunately,  these  primitive  little  beings  are 
ignored  or  neglected  by  most  biologists  to-day.  O. 
Hertwig  devotes  one  page  of  his  three  -  hundred  -  page 
book  on  cells  and  tissues  to  them;  he  doubts  the  exist- 
ence of  cells  without  nuclei.  Reinke,  who  has  himself 
shown  the  existence  of  unnucleated  cells  among  the 
bacteria  (beggiatoa),  does  not  say  a  word  about  their 
general  significance.  Biitschli,  who  shares  my  monis- 
tic conception  of  life,  and  has  given  it  considerable 
support  by  his  own  thorough  study  of  plasma- 
structures  and  the  artificial  production  of  them 
in  oil  and  soapsuds,  believes,  like  many  other 
writers,   that   the   "composition   of   even   the   simplest 

31 


THE    WONDERS    OF    LIFE 

elementary  organism  from  cell-nucleus  and  proto- 
plasm" (the  primitive  organs  of  the  cell)  is  indispensable. 
These  and  other  writers  suppose  that  the  nucleus  has 
been  overlooked  in  the  protoplasm  of  the  monera  I  have 
described.  This  may  be  true  for  one  section  of  them; 
but  they  say  nothing  about  the  other  section,  in  which 
the  nucleus  is  certainly  lacking.  To  this  class  belong 
the  remarkable  chromacea  {phycochroniacea  or  cyanophy- 
cea),  and  especially  the  simplest  forms  of  these,  the 
chroococcacea  (chroococcus,  aphanocapsa,  glceocapsa,  etc.). 
These  plasmodomous  (plasma-forming)  monera,  which 
live  at  the  very  frontier  of  the  organic  and  inorganic 
worlds,  are  by  no  means  uncommon  or  particularly 
difficult  to  find;  on  the  contrar3^  they  are  found  every- 
where, and  are  easy  to  observe.  Yet  they  are  generally 
ignored  because  they  do  not  square  with  the  prevailing 
dogma  of  the  cell. 

I  ascribe  this  special  significance  to  the  chromacea 
among  all  the  monera  I  have  instanced  because  I  take 
them  to  be  the  oldest  phyletically,  and  the  most  primi- 
tive of  all  living  organisms  known  to  us.  In  particular 
their  very  simple  forms  correspond  exactly  to  all  the 
theoretic  claims  which  monistic  biology  can  make  as  to 
the  transition  from  the  inorganic  to  the  organic.  Of  the 
chroococcacea,  the  chroococcus,  gloeocapsa,  etc.,  are 
found  throughout  the  world;  they  form  thin,  usually 
bluish -green  coats  or  jelly-like  deposits  on  damp  rocks, 
stones,  bark  of  trees,  etc.  When  a  small  piece  of  this  jelly 
is  examined  carefully  under  a  powerful  microscope,  noth- 
ing is  seen  but  thousands  of  tiny  blue-green  globules  of 
plasma,  distributed  irregularly  in  the  common  structure- 
less mass.  In  some  species  we  can  detect  a  thin  struct- 
ureless membrane  enclosing  the  homogeneous  particle  of 
plasm;  its  origin  can  be  explained  on  purely  physical 
principles  by  "superficial  energy" — like  the  firmer  sur- 
face-layer of  a  drop  of  rain,  or  of  a  globule  of  oil  swim- 

32 


LIFE 

ming  in  water.  Other  species  secrete  homogeneous  jelly- 
like  envelopes — a  purely  chemical  process.  In  some  of 
the  chromacea  the  blue-green  coloring  matter  {phyocyan) 
is  stored  in  the  surface-layer  of  the  particle  of  plasm, 
while  the  inner  part  is  colorless — a  sort  of  "central 
body."  However,  the  latter  is  by  no  means  a  real, 
chemically  and  morphologically  distinct,  nucleus.  Such 
a  thing  is  completely  lacking.  The  whole  life  of  these 
simple,  motionless  globules  of  plasm  is  confined  to  their 
metabolism  (or  plasniodomism,  chapter  x.)  and  the  re- 
sulting growth.  When  the  latter  passes  a  certain  stage, 
the  homogeneous  globule  splits  into  two  halves  (like  a 
drop  of  quicksilver  when  it  falls).  This  simplest  form  of 
reproduction  is  shared  by  the  chromacea  (and  the 
cognate  bacteria)  with  the  chromatella  or  chromato- 
phora,  the  green  particles  of  chlorophyll  inside  ordinary 
plant-cells ;  but  these  are  only  parts  of  a  cell.  Hence  no 
unprejudiced  observer  can  compare  these  unnucleated 
and  independent  granules  of  plasm  with  real  (nucleated) 
cells,  but  must  conceive  them  rather  as  cytodes.  These 
anatomic  and  physiological  facts  may  easily  be  observed 
in  the  chromacea,  which  are  found  everywhere.  The 
organism  of  the  simplest  chromacea  is  really  nothing 
more  than  a  stmctureless  globular  particle  of  plasm; 
we  cannot  discover  in  them  any  composition  of  dif- 
ferent organs  (or  organella)  for  definite  vital  functions. 
Such  a  composition  or  organization  would  have  no 
meaning  in  this  case,  since  the  sole  vital  purpose  of 
these  plasma-particles  is  self-maintenance.  This  is 
attained  in  the  simplest  fashion  for  the  individual 
by  metabolism;  for  the  species  it  is  effected  by  self- 
cleavage,  the  simplest  conceivable  form  of  reproduc- 
tion. 

Modern  histologists  have  discovered  a  very  intricate 
and  delicate  structure  in  many  of  the  higher  unicellular 
protists  and  in  many  of  the  tissue-cells  of  the  higher 


THE    WONDERS    OF    LIFE 

animals  and  plants  (such  as  the  nerve-cells).  They 
wrongly  conclude  that  this  is  universal.  In  my  opinion, 
this  complication  of  the  structure  of  the  elementary 
organism  is  always  a  secondary  phenomenon,  the  slow 
and  gradual  result  of  countless  phylogenetic  processes  of 
differentiation,  initiated  by  adaptation  and  transmitted 
to  posterity  by  heredity.  The  earliest  ancestors  of  all 
these  elaborate  nucleated  cells  were  at  first  simple,  un- 
nucleated  cytodes,  such  as  we  find  to-day  in  the  ubiq- 
uitous monera.  We  shall  see  more  about  them  in  the 
ninth  and  fifteenth  chapters. 

Naturally,  this  lack  of  a  visible  histological  structure 
in  the  plasma-globule  of  the  monera  does  not  exclude  the 
possession  of  an  invisible  molecular  structure.  On  the 
contrary,  we  are  bound  to  assume  that  there  is  such  a 
structure,  as  in  all  albuminoid  compounds,  and  espe- 
cially all  plasmic  bodies.  But  we  also  find  this  elaborate 
chemical  structure  in  many  lifeless  bodies;  some  of 
these,  in  fact,  show  a  metabolism  similar  to  that  of  the 
simplest  organisms.  We  will  return  subsequently  to 
this  subject  of  catalysis.  Briefly,  the  only  difference 
between  the  simplest  chromacea  and  inorganic  bodies 
that  have  catalysis  is  in  the  special  form  of  their  metab- 
olism, which  we  call  plasmodomism  (formation  of 
plasm),  or  "carbon-assimilation."  The  mere  fact  that 
the  chromacea  assume  a  globular  form  is  no  sign  what- 
ever of  a  morphological  vital  process;  drops  of  quick- 
silver and  other  inorganic  fluids  take  the  same  shape 
when  the  individual  body  is  formed  under  certain  condi- 
tions. When  a  drop  of  oil  falls  into  a  fluid  of  the  same 
specific  gravity  with  which  it  cannot  mix  (such  as  a 
mixture  of  water  and  spirits  of  wine),  it  immediately 
assumes  a  globular  shape.  Inorganic  solids  usually  take 
_the  form  of  crystals  instead.  Hence  the  distinctive 
feature  of  the  simplest  organism,  the  plasma-particles 
of   the   monera,   is   neither   anatomic   structure   nor   a 

34 


LIFE 

certain  shape,  but  solely  the  physiological  function  of 
plasmodomism — a  process  of  chemical  synthesis. 

The  difference  between  the  monera  I  have  described 
and  any  higher  organism  is,  I  think,  greater  in  every 
respect  than  the  difference  between  the  organic  monera 
and  the  inorganic  crystals.  Nay,  even  the  difference 
between  the  unnucleated  monera  (as  cytodes)  and  the 
real  nucleated  cells  may  fairly  be  regarded  as  greater 
still.  Even  in  the  simplest  real  cell  we  find  the  distinc- 
tion between  two  different  organella,  or  "cell-organs," 
the  internal  nucleus  and  the  outer  cell-body.  The 
caryoplasm  of  the  nucleus  discharges  t!ie  functions  of 
reproduction  and  heredity;  the  cytoplasm  of  the  cell- 
body  accomplishes  the  metabolism,  nutrition,  and  adap- 
tation. Here  we  have,  therefore,  the  first,  oldest,  and 
most  important  process  of  division  of  labor  in  the 
elementary  organism.  In  the  unicellular  protists  the 
organization  rises  in  proportion  to  the  differentiation  of 
the  various  parts  of  the  cell;  in  the  tissue-forming 
histona  it  rises  again  in  proportion  to  the  distribution 
of  work  (or  ergonomy)  among  the  various  organs. 
Darwin  has  given  us  in  his  theory  of  selection  a  me- 
chanical explanation  of  the  apparent  design  and  pur- 
posiveness  in  this. 

In  order  to  have  a  correct  monistic  conception  of 
organization,  it  is  important  to  distinguish  the  individ- 
uality of  the  organism  in  its  various  stages  of  composi- 
tion. We  shall  treat  this  important  question,  about 
which  there  is  a  good  deal  of  obscurity  and  contradiction, 
in  a  special  chapter  (vii.).  It  suffices  for  the  moment 
to  point  out  that  the  unicellular  beings  (protists)  are 
simple  organisms  both  in  regard  to  morphology  and 
physiology.  On  the  other  hand,  this  is  only  true  in  the 
physiological  sense  of  the  histona,  the  tissue-forming 
animals  and  plants.  From  the  morphological  point  of 
view  they  are  made  up  of  innumerable  cells,  which  form 

35 


THE    WONDERS    OF    LIFE 

the  various  tissues.  These  histonal  individuals  are 
called  sprouts  in  the  plant  world  and  persons  in  the  ani- 
mal world.  At  a  still  higher  stage  of  organization  we 
have  the  trunk  or  stem  (cormus),  which  is  made  up  of  a 
number  of  sprouts  or  persons,  like  the  tree  or  the  coral- 
stem.  In  the  fixed  animal  stems  the  associated  individ- 
uals have  a  direct  bodily  connection,  and  take  their 
food  in  common;  but  in  the  social  aggregations  of  the 
higher  animals  it  is  the  ideal  link  of  common  interest  that 
unites  the  individuals,  as  in  swarms  of  bees,  colonies  of 
ants,  herds  of  mammals,  etc.  These  communities  are 
sometimes  called  "animal-states."  Like  human  polities, 
they  are  organisms  of  a  higher  type. 

However,  in  order  to  avoid  misunderstanding,  we 
must  take  the  word  "organism"  in  the  sense  in  which 
most  biologists  use  it — namely,  to  designate  an  in- 
dividual living  thing,  the  material  substratum  of  which 
is  plasm  or  "living  substance" — a  nitrogenous  carbon- 
compound  in  a  semi-fluid  condition.  It  leads  to  a  good 
deal  of  misunderstanding  when  separate  functions  are 
called  organisms,  as  is  done  sometimes  in  speaking  of  the 
soul  or  of  speech.  It  would  be  just  as  correct  to  call  see- 
ing or  running  an  organism.  It  is  advisable  also  in 
scientific  treatises  to  refrain  from  calling  inorganic 
compounds  as  such  "organisms,"  as,  for  instance,  the 
sea  or  the  whole  earth.  Such  names,  having  a  purely 
symbolical  value,  may  very  well  be  used  in  poetry.  The 
rhythmic  wave-movement  of  the  ocean  may  be  re- 
garded as  its  respiration,  the  surge  as  its  voice,  and  so 
on.  Many  scientists  (like  Fechner)  conceive  the  whole 
earth  Vv^ith  all  its  organic  and  inorganic  contents  as  a 
gigantic  organism,  whose  countless  organs  have  been 
arranged  in  an  orderly  whole  by  the  world-reason 
(God).  In  the  same  way  the  physiologist,  Preyer,  re- 
gards the  glowing  heavenly  bodies  as  "gigantic  or- 
ganisms, whose  breath  is,  perhaps,  the  glowing  vapor 

36 


LIFE 

of  iron,  whose  blood  is  liquid  metal,  and  whose  food  may- 
be meteorites."  The  danger  of  this  poetic  application 
of  the  metaphorical  sense  of  organism  is  very  well  seen 
in  this  instance,  as  Preyer  builds  on  it  a  quite  un- 
tenable hypothesis  of  the  origin  of  life  (see  chapter  xv.). 

In  the  wider  sense  the  word  "organic"  has  long  been 
used  in  chemistry  as  an  antithesis  to  inorganic.  By 
organic  chemistry  is  generally  understood  the  chemistry 
of  the  compounds  of  carbon,  that  element  being  dis- 
tinguished from  all  the  others  (some  seventy-eight  in 
number)  by  very  important  properties.  It  has,  in  the 
first  place,  the  property  of  entering  into  an  immense 
varietv  of  combinations  with  other  elements,  and 
especially  of  uniting  with  oxygen,  hydrogen,  nitrogen, 
and  sulphur  to  form  the  most  complicated  albtiminoids 
(see  the  Riddle,  chapter  xiv.).  Carbon  is  a  biogenetic 
element  of  the  first  importance,  as  I  explained  in  my 
carbon-theory  in  1866.  It  might  even  be  called  "the 
creator  of  the  organic  world."  At  first  these  organo- 
genetic  compounds  do  not  appear  in  the  organism  in 
organized  form — that  is  to  say,  they  are  not  yet  distrib- 
uted into  organs  with  definite  purposes.  Such  organi- 
zation is  a  result,  not  the  cause,  of  the  life-process. 

I  have  already  shown  in  the  fourteenth  chapter  of  the 
Riddle  (and  at  greater  length  in  the  fifteenth  chapter  of 
my  History  of  Creation)  that  the  belief  in  the  essential 
unity  of  nature,  or  the  monism  of  the  cosmos,  is  of  the 
greatest  importance  for  our  whole  system.  I  gave  a 
very  thorough  justification  of  this  cosmic  monism  in 
1866.  In  the  fifth  chapter  of  the  Generelle  Morphologic 
I  considered  the  relation  of  the  organic  to  the  in- 
organic in  every  respect,  pointing  out  the  differences 
between  them  on  the  one  hand,  and  their  points  of  agree- 
ment in  matter,  form,  and  force  on  the  other.  Niigeli 
some  time  afterwards  declared  similarly  for  the  unity  of 
nature  in  his  able  MechaniscJi-physiologische  Bcgriindung 

.37 


THE    WONDERS    OF    LIFE 

der  Ahstamniiingslehre  (1884).  Wilhelm  Ostwald  has 
recently  done  the  same,  from  the  monistic  point  of  view 
of  his  system  of  energy,  in  his  NaUirphilosophie,  espe- 
cially in  the  sixteenth  chapter.  Without  being  acquaint- 
ed with  my  earlier  work,  he  has  impartially  compared 
the  physico-chemical  processes  in  the  organic  and  inor- 
ganic worlds,  partly  adducing  the  same  illustrations 
from  the  instructive  field  of  crystallization.  He  came 
to  the  same  monistic  conclusions  that  I  reached  thirty- 
six  years  ago.  As  most  biologists  continue  to  ignore 
them,  and  as,  especially,  modern  vitalism  thrusts  these 
inconvenient  facts  out  of  sight,  I  will  give  a  brief  sum- 
mary once  more  of  the  chief  points  as  regards  the  matter, 
form,  and  forces  of  bodies. 

Chemical  analysis  shows  that  there  are  no  elements 
present  in  organisms  that  are  not  found  in  inorganic 
bodies.  The  number  of  elements  that  cannot  be  further 
analyzed  is  now  put  at  seventy-eight ;  but  of  these  only 
the  five  organogenetic  elements  already  mentioned  which 
combine  to  form  plasm — carbon,  oxygen,  hydrogen, 
nitrogen,  and  sulphur — are  found  invariably  in  living 
things.  With  these  are  generally  (but  not  always) 
associated  five  other  elements — phosphor,  potassium, 
calcium,  magnesium,  and  iron.  Other  elements  may  also 
be  found  in  organisms ;  bu  t  there  is  not  a  single  biological 
element  that  is  not  also  found  in  the  inorganic  world. 
Hence  the  distinctive  features  which  separate  the  one 
from  the  other  can  be  sought  only  in  some  special  form 
of  combination  of  the  elements.  And  it  is  carbon  es- 
pecially, the  chief  organic  element,  that  by  its  peculiar 
affinity  enters  into  the  most  diverse  and  complicated 
combinations  with  other  elements,  and  produces  the 
m.ost  important  of  all  substances,  the  albuminoids,  at 
the  head  of  which  is  the  living  plasm  {cf.  chapter  vi.). 

An  indispensable  condition  of  the  circulation  of  matter 
(metabolism)  which  we  call  life  is  the  physical  process  of 


LIFE 

osmosis,  which  is  connected  with  the  variations  in  the 
quantity  of  water  in  the  hving  substance  and  its  power  of 
diffusion.  The  plasm,  which  is  of  a  spongy  or  viscous 
consistency,  can  take  in  dissolved  matter  from  without 
(endosmosis)  and  eject  matter  from  within  (exosmosis). 
This  absorptive  property  (or  "imbibition-energy")  of 
the  plasm  is  connected  with  the  colloidal  character  of  the 
albuminoids.  As  Graham  has  shown,  we  may  divide  all 
soluble  substances  into  two  groups  in  respect  of  their 
diosmosis — crystalloids  and  colloids.  Crystalloids  (such 
as  soluble  salt  and  sugar)  pass  more  easily  into  water 
through  a  porous  wall  than  colloids  (such  as  albumen, 
glue,  gum,  caramel).  Hence  we  can  easily  separate  by 
dialysis  two  bodies  of  different  groups  which  are  mixed 
in  a  solution.  For  this  we  need  a  flat  bottle  with  side 
walls  of  india-rubber  and  bottom  of  parchment.  If  we 
let  this  vessel  float  in  a  large  one  containing  plenty  of 
water,  and  pour  a  mixture  of  dissolved  gum  and  sugar 
into  the  inner  vessel,  after  a  time  nearly  all  the  sugar 
passes  through  the  parchment  into  the  water,  and  an 
almost  pure  solution  of  gum  remains  in  the  bottle.  This 
process  of  diffusion,  or  osmosis,  plays  a  most  important 
part  in  the  life  of  all  organisms;  but  it  is  by  no  means 
peculiar  to  the  living  substance,  any  more  than  the 
absorptive  or  viscous  condition  is.  We  may  even  have 
one  and  the  same  substance — either  organic  or  inorganic 
— in  both  conditions,  as  crystal  or  as  colloid.  Albumen, 
which  usually  seems  to  be  colloidal,  forms  hexagonal 
crystals  in  many  plant-cells  (for  instance,  in  the  aleuron- 
granules  of  the  endosperm),  and  tetrahedric  hoemoglobin- 
crystals  in  many  animal-cells  (as  in  the  blood  corpuscles 
of  mammals).  These  albuminoid  crystals  are  distin- 
guished by  their  capacity  for  absorbing  a  considerable 
quantity  of  water  without  losing  their  shape.  On  the 
other  hand,  mineral  silicon,  which  appears  as  quartz  in 
an  immense  variety  (more  than  one  hundred  and  sixty) 

39 


THE    WONDERS    OF    LIFE 

of  crystalline  forms,  is  capable  in  certain  circum- 
stances (as  metasilicon)  of  becoming  colloidal  and  form- 
ing jelly-like  masses  of  glue.  This  fact  is  the  more 
interesting  because  silicium  behaves  in  other  ways  very 
like  carbon,  is  quadrivalent  like  it,  and  forms  very 
similar  combinations.  Amorphous  (or  non-crystalline) 
silicium  (a  brown  powder)  stands  in  relation  to  the  black 
metallic  silicon-crystals  just  as  amorphous  carbon  does 
to  graphite-crystals.  There  are  other  substances  that 
may  be  either  crystalloid  or  colloid  in  different  circum- 
stances. Hence,  however  important  colloidal  structure 
may  be  for  the  plasm  and  its  metabolism,  it  can  by  no 
means  be  advanced  as  a  distinctive  feature  of  living 
matter. 

Nor  is  it  possible  to  assign  an  absolute  distinction 
between  the  organic  and  the  inorganic  in  respect  of 
morphology  any  more  than  of  chemistry.  The  instruc- 
tive monera  once  more  form  a  connecting  bridge  be- 
tween the  two  realms.  This  is  true  both  of  the  inter- 
nal structure  and  the  outward  form  of  both  classes 
of  bodies — of  their  individuality  (chapter  vii.)  and  their 
r  type  (chapter  viii.).  Inorganic  crystals  correspond  mor- 
phologically to  the  simplest  (unnucleated)  forms  of 
the  organic  cells.  It  is  true  that  the  great  majority 
of  organisms  seem  to  be  conspicuously  different  from 
inorganic  bodies  by  the  mere  fact  that  they  are  made  up 
of  many  different  parts  which  they  use  as  organs  for 
definite  purposes  of  life.  But  in  the  case  of  the  monera 
there  is  no  such  organization.  In  the  simplest  cases 
(chromacea,  bacteria)  they  are  structureless,  globular, 
discoid,  or  rod-shaped  plasmic  individuals,  which  accom- 
plish their  peculiar  vital  function  (simple  growth  and 
subdivision)  solely  by  means  of  their  chemical  constitu- 
tion, or  their  invisible  molecular  structure. 

The  comparison  of  cells  with  crystals  was  made  in 
1838  by  the  founders  of  the  cell-theory,  Schleiden  and 

40 


LIFE 

Schwann.  It  has  been  much  criticised  by  recent  cytol- 
ogists,  and  does  not  hold  in  all  respects.  Still  it  is  of 
importance,  as  the  crystal  is  the  most  ])erfect  form  of 
inorganic  individuality,  has  a  definite  internal  structure 
and  outward  form,  and  obtains  these  by  a  regular  growth. 
The  external  form  of  crystals  is  prismatic,  and  bounded 
by  straight  surfaces  which  cut  each  other  at  certain 
angles.  But  the  same  form  is  seen  in  the  skeletons  of 
many  of  the  protists,  especially  the  flinty  shells  of  the 
diatomes  and  radiolaria;  their  silicious  coverings  lend 
themselves  to  mathematical  determination  just  as  well 
as  the  inorganic  crystals.  Midway  between  the  organic 
plasma-products  and  inorganic  crystals  we  have  the 
bio-crystals,  which  are  formed  by  the  united  plastic 
action  of  the  plasm  and  the  mineral  matter — for  in- 
stance, the  crystalline  flint  and  chalk  skeletons  of 
many  of  the  sponges,  corals,  etc.  Further,  by  the 
orderly  association  of  a  number  of  crystals  we  get  com- 
pound crystal  groups,  which  may  be  compared  to  the 
communities  of  protists — for  instance,  the  branching 
ice-flowers  and  ice-trees  on  the  frozen  window.  To 
this  regular  external  form  of  the  crystal  corresponds  a 
definite  internal  structure  which  shows  itself  in  their 
cleavage,  their  stratified  build,  their  polar  axes,  etc. 

If  we  do  not  restrict  the  term  "life"  to  organisms 
properly  so-called,  and  take  it  only  as  a  function  of 
plasm,  we  may  speak  in  a  broader  sense  of  the  life  of 
crystals.  This  is  seen  especially  in  their  growth,  the 
phenomenon  which  Baer  regarded  as  the  chief  character 
of  all  individual  development.  When  a  crystal  is  formed 
in  a  matrix,  this  is  done  by  attracting  homogeneous 
particles.  When  two  different  substances,  A  and  B,  are 
dissolved  in  a  mixed  and  saturated  solution,  and  a 
crystal  of  A  is  put  in  the  mixture,  only  A  is  crystallized 
out  of  it,  not  B;  on  the  other  hand,  if  a  crystal  of  B  is 
put  in,  A  reraains  in  solution  and  B  alone  assumes  the 

41 


THE    WONDERS    OF    LIFE 

solid  crystalline  form.  We  may,  in  a  certain  sense,  call 
this  choice  assimilation.  In  many  crystals  we  can 
detect  internally  an  interaction  of  their  parts.  When  we 
cut  off  an  angle  in  a  forming  crystal,  the  opposite  angle 
is  only  imperfectly  formed.  A  more  important  difference 
between  the  growth  of  crystals  and  monera  is  that  the 
former  only  grow  by  apposition,  or  the  deposit  of  fresh 
solid  matter  at  their  surface;  while  the  monera  grow, 
like  all  cells,  by  iutitssusception,  or  the  taking  of  new 
matter  into  their  interior.  But  this  difference  is  easily 
explained  by  their  difference  in  consistency,  the  crystal 
being  solid  and  the  plasm  semi-fluid.  Moreover,  the 
difference  is  not  absolute;  there  are  intermediary  stages 
between  apposition  and  intussusception.  A  colloid 
globule  suspended  in  a  salt  solution  in  which  it  is  not 
dissolved  may  grow  by  intussusception. 

It  was  once  the  custom  to  restrict  sensation  and 
movement  to  animals,  but  they  are  now  recognized  to  be 
present  in  nearly  all  living  matter.  They  are,  in  fact, 
not  altogether  lacking  in  crystals,  as  the  molecules  move 
in  crystallization  in  definite  directions,  and  unite  accord- 
ing to  fixed  laws;  they  must,  therefore,  also  possess 
sensation,  as  we  could  not  otherwise  understand  the 
attraction  of  the  homogeneous  particles.  We  find  in 
crystallization,  as  in  every  chemical  process,  certain 
movements  which  are  unintelligible  without  sensation — 
unconscious  sensation,  of  course.  In  this  respect,  also, 
then,  the  growth  of  all  bodies  follows  the  same  laws 
{cf.  chapters  xiii.  and  xv.). 

The  growth  of  a  crystal  is  restricted  like  the  growth 
of  a  moneron  or  of  any  cell.  If  the  limit  is  passed  and 
the  conditions  remain  favorable  to  growth,  we  find  an 
instance  of  that  excessive  or  transgressive  growth  which 
we  call  reproduction  in  the  case  of  living  individuals. 
Bvit  we  find  just  the  same  kind  of  extension  in  the 
inorganic    crystal.     Every    crystal   grows    in   a   super- 

42 


LIFE 

saturated  medium  only  up  to  a  definite  size,  which 
is  determined  by  its  chemical-molecular  constitution. 
When  this  limit  is  reached  a  number  of  small  crystals 
appear  on  the  large  one.  Ostwald,  who  has  made  a 
thorough  comparison  of  the  process  of  growth  in  crystals 
and  monera,  especially  notices  the  striking  analogy 
between  a  bacterium  (a  plasmophagous  moneron) 
growing  and  multiplying  in  its  nutritive  fluid  and  a 
crystal  in  its  matrix.  When  the  water  slowly  evaporates 
from  a  supersaturated  solution  of  Glauber-salt,  not  only 
does  a  crystal  slowly  grow  in  it,  but  several  young 
crystals  appear  on  it.  The  analogy  with  the  bacterium 
multiplying  in  its  nutritive  fluid  can  even  be  followed  as 
far  as  its  permanent  forms  or  "spores."  This  quiescent 
form  is  assumed  by  the  bacterium  if  its  supply  of  food 
is  exhausted;  if  fresh  food  is  added,  the  multiplication 
by  cleavage  begins  again.  In  the  same  way  the  crys- 
tals of  Glauber-salt  begin  to  decay  when  the  solution 
is  evaporated;  they  lose  their  crystal  water,  but  not 
their  power  of  multiplication.  Even  the  amorphous 
powder  of  the  salt  causes  again  the  formation  of  new 
watery  crystals  when  put  in  a  supersaturated  solution. 
But  the  powder  loses  this  property  when  it  is  heated, 
just  as  the  dormant  forms  (or  spores)  of  the  bacteria 
lose  their  power  of  germination. 

The  exhaustive  comparison  of  the  growth  of  crystals 
and  monera  (as  the  simplest  forms  of  unnucleated  cells) 
is  important,  because  it  shows  the  possibility  of  tracing 
the  vital  function  of  reproduction — which  had  usually 
been  regarded  as  a  quite  special  "wonder  of  life" — to 
purely  physical  conditions.  The  division  of  the  growing 
individual  into  several  young  ones  must  necessarily  take 
place  when  the  natural  limit  of  growth  has  been  passed, 
and  when  the  chemical  composition  of  the  growing  body 
and  the  cohesion  of  its  molecules  allow  no  further  en- 
largement by  the  assumption  of  new  matter.     In  order 

43 


THE    WONDERS    OF    LIFE 

to  illustrate  the  limit  of  this  transgressive  growth  by  a 
simple  physical  example,  Ostwald  imagines  a  ball  placed 
in  a  small  flat  basin,  built  up  high  on  one  side.  The 
ball  is  in  a  state  of  equilibrium  in  the  basin;  when  it  is 
lightly  pushed  aside  it  always  returns  to  its  original 
position.  But  when  the  push  goes  beyond  a  certain 
point,  and  the  ball  is  thrust  over  the  side  of  the  basin, 
the  balance  is  lost;  the  ball  does  not  return,  but  falls  to 
the  ground.  The  crystal  behaves  just  in  the  same  way 
in  a  supersaturated  solution  when  it  exercises  its  power 
of  forming  new  crystals;  and  it  is  just  the  same  with 
the  bacterium  growing  in  a  nutritive  fluid  when  it 
passes  the  limit  of  its  volume  of  growth,  and  divides 
into  two  individuals. 

As  we  can  find  no  morphological  and  little  physiological 
difference  between  the  living  and  non-living,  we  must 
look  upon  metabolism  as  the  chief  characteristic  of  or- 
ganic life.  This  process  causes  the  conversion  of  food  into 
plasm;  it  is  determined  by  the  vital  force  itself,  and  is 
the  formation  of  new  living  matter.  It  thus  effects  the 
nutrition  and  growth  of  the  living  being,  and  therefore 
its  reproduction,  which  is  merely  transgressive  growth. 
As  I  shall  describe  this  metabolism  fully  in  the  tenth 
chapter,  I  will  do  no  more  here  than  emphasize  the  fact 
that  this  vital  process  also  has  analogies  in  inorganic 
chemistry,  in  the  curious  process  of  catalysis,  especially 
that  form  of  it  which  we  call  fermentation. 

The  distinguished  chemist  Berzelius  discovered  in 
1810  the  remarkable  fact  that  certain  bodies,  by  their 
mere  presence,  apart  from  their  chemical  affinity,  set 
other  bodies  in  decomposition  or  composition  without 
being  themselves  affected.  Thus,  for  instance,  sulphuric 
acid  changes  the  starch  in  sugar  without  undergoing 
any  alteration  itself.  Finely  ground  platinum  brought 
in  contact  with  hydrogen-superoxide  divides  it  into 
hydrogen    and    oxygen.     Berzelius    called    this   process 

44 


LIFE 

catalysis;  Mitscherlich,  who  discovered  the  cause  of  it 
to  be  the  pecuHar  surface  -  action  of  many  bodies, 
gave  it  the  name  of  "contact -action."  It  was  after- 
wards discovered  that  catalysis  of  this  kind  is  very 
general,  and  that  a  special  form  of  it  —  fermenta- 
tion —  plays  an  important  part  in  the  life  of  organ- 
isms. 

This  special  form  of  contact-action  which  we  call 
fermentation  is  always  effected  by  catalytic  bodies  of  the 
albuminoid  class,  and,  in  fact,  of  the  group  of  non- 
coagulable  proteins  which  are  known  as  peptones.  They 
have — in  however  small  a  quantity — the  capacity  to 
throw  into  decomposition  large  masses  of  organic  matter 
(in  the  form  of  yeast,  putrid  matter,  etc.)  without  them- 
selves taking  part  in  the  decomposition.  When  these  j 
ferments  are  free  and  unorganized  they  are  called 
enzyma,  in  opposition  to  organized  ferments  (bacteria, 
yeast-fungi,  etc.);  though  the  catalytic  action  of  the 
latter  also  consists  essentially  in  the  production  of 
enzyma.  The  recent  investigations  of  Verworn,  Hof- 
meister,  Ostwald,  etc.,  have  shown  that  these  catalyses 
play  everywhere  an  important  part  in  the  life  of  the 
plasm.  Many  recent  chemnsts  and  physiologists  are  of 
opinion  that  plasm  is  a  colloid  catalysator,  and  that  all 
the  varied  activities  of  life  are  connected  with  this  funda- 
mental vital  chemistry.  Thus  Franz  Hofmeister  (1901) 
says  in  his  excellent  work  on  The  Chemical  Organization 
of  the  Cell: 

The  belief  that  the  agents  of  the  chemical  transformation  in 
the  cell  are  catalysators  of  a  colloid  nature  is  in  complete  accord 
with  other  facts  that  have  been  directly  ascertained.  What  else 
are  the  chemists'  ferments  but  colloid  catalysators  ?  The  idea 
that  the  ferments  are  the  essential  chemical  ai^ency  in  the  cell  is 
calculated  to  meet  the  difficulty  which  arises  from  the  smallness 
of  the  cell  in  appreciating  its  chemical  processes.  However 
large  we  suppose  the  colloid  ferment  molecules  to  be,  there  is 
room  for  millions  of  them  in  the  smallest  cell. 

45 


THE    WONDERS    OF    LIFE 

In  the  same  way  Ostwald  attributes  the  greatest 
significance  to  catalysis  in  connection  with  the  vital 
processes,  and  seeks  to  explain  them  on  his  theory  of 
energy  by  reference  to  the  duration  of  chemical  proc- 
esses. In  the  discourse  "On  Catalysis"  that  he  de- 
livered at  Hamburg  in  1901  he  says: 

We  must  recognize  the  enzyma  as  catalysators  that  arise  in 
the  organism  during  the  life  of  the  cells,  and  by  their  action 
relieve  the  living  being  of  the  greater  part  of  its  duties.  Not 
only  are  digestion  and  assimilation  controlled  by  enzyma  from 
first  to  last,  but  the  fundamental  vital  action  of  most  organisms, 
the  production  of  the  necessary  chemical  energy  by  combustion 
at  the  expense  of  the  oxygen  in  the  air,  takes  place  with  the 
explicit  co-operation  of  enzyma,  and  would  be  impossible  with- 
out them.  Free  oxygen  is,  as  is  well  known,  a  very  inert  body 
at  the  temperature  of  the  living  body,  and  the  maintenance 
of  life  would  be  impossible  without  some  acceleration  of  its 
rate  of  reaction. 

In  his  further  observations  on  catalysis  and  metabolism 
he  says  that  they  are  both  equally  subject  to  the  physico- 
chemical  laws  of  energy. 

Max  Verworn  has  given  us  a  very  searching  analysis 
of  the  molecular  process  in  the  catalytic  aspect  of  metab  • 
olism  in  his  Biogen  Hypothesis  (1903),  "a  critical  and 
experimental  study  of  the  processes  in  living  matter." 
He  simplifies  the  catalytic  theory  of  the  enzyma  by 
tracing  all  the  phenomena  of  life  to  the  catalytic  metab- 
olism of  one  single  chemical  compound,  the  plasm,  and 
regards  its  active  molecules,  the  biogens,  as  the  ultimate 
chemical  factors  of  the  vital  process.  While  the  enzyma 
hypothesis  assumes  that  there  are  in  each  cell  a  great 
number  of  different  enzyma  which  are  all  co-ordinated, 
and  each  of  which  only  performs  its  little  special  work, 
the  biogen  hypothesis  deduces  all  the  vital  phenomena 
from  one  compound,  the  biogenetic  plasm;  and  thus  the 
biogen  molecules,  which  increase  by  division  into  parts, 

46 


LIFE 

are  the  sole  factors  of  biological  catalysis.  Verworn 
also  points  out  the  analogy  between  this  enzymatic 
process  of  metabolism  and  the  inorganic  processes  of 
catalysis — for  instance,  in  the  manufacture  of  English 
sulphuric  acid.  A  small  and  constant  quantity  of  nitro- 
muriatic  acid,  with  the  aid  of  air  and  water,  converts  an 
unlimited  mass  of  sulphuretted  acid  into  sulphuric  acid 
without  being  changed  itself;  the  molecule  of  the  nitro- 
muriatic  acid  breaks  up  steadily  by  the  giving-off  of 
oxygen,  and  is  then  restored  by  the  assumption  of 
oxygen. 

The  manifold  and  changeful  phenomena  of  life  and 
their  sudden  extinction  at  death  seem  to  every  thoughtful 
man  to  be  something  so  wonderful  and  so  different  from 
all  the  changes  in  inorganic  nature  that  from  the  very 
beginning  of  biological  philosophy  special  forces  were 
assumed  to  explain  it.  This  was  particularly  due  to  the 
remarkable,  orderly  structure  of  the  organism  and  the 
apparent  purposiveness  of  the  vital  processes.  Hence,  in 
earlier  days  a  special  organic  force  {archcBus  insitns)  was 
assumed,  controlling  the  individual  life  and  pressing  the 
"raw  forces"  of  inorganic  matter  into  its  service.  In 
the  same  way  a  special  formative  impulse  was  supposed 
to  preside  over  the  wonderful  processes  of  development. 
When  physiology  began  to  win  its  independence,  about 
the  middle  of  the  eighteenth  century,  it  explained  the 
peculiar  features  of  organic  life  by  a  specific  vital  force. 
The  idea  was  generally  received,  and  Louis  Dumas 
endeavored  thoroughly  to  establish  it  at  the  beginning 
of  the  nineteenth  century  {cf.  chapter  iii.  of  the  Riddle). 

As  the  theory  of  a  vital  force,  or  vitalism,  plays  an 
important  part  in  the  study  of  the  wonders  of  life,  has 
undergone  the  most  curious  modifications  in  the  course 
of  the  nineteenth  century,  and  has  been  lately  revived 
with  great  force,  we  must  give  a  short  account  of  it  in 
its  various  forms.     The  phrase  can  be  interpreted  in  a 

47 


THE    WONDERS    OF    LIFE 

monistic  sense,  if  we  understand  bv  it  the  sum  of  the 
forms  of  energy  which  are  especially  distinctive  of  the 
organism,  particularly  metabolism  and  heredity.  In 
this  we  pass  no  opinion  on  their  nature,  and  do  not  say 
that  they  are  specifically  different  from  the  forces  of 
inorganic  nature.  We  might  call  this  monistic  concep- 
tion "physical  vitalism."  However,  the  usual  meta- 
physical vitalism  affirms  in  a  thoroughly  dualistic  sense 
that  the  vital  force  is  a  teleological  and  super-mechanical 
principle,  is  essentially  different  from  the  ordinar}?- 
forces  of  nature,  and  of  a  transcendental  character. 
The  special  form  in  which  this  theory  of  a  supernatural 
vital  force  has  been  presented  for  the  last  twenty  years 
is  often  called  Neovitalism;  we  might  call  the  older 
form,  by  contrast,  Palavitalism. 

The  older  idea  of  the  vital  force  as  a  special  energy 
could  very  well  be  accepted  in  the  first  third  of  the  nine- 
teenth century,  and  in  the  eighteenth,  because  the 
physiology  of  the  time  was  destitute  of  the  most  im- 
portant aids  to  the  founding  of  a  mechanical  theory. 
There  was  then  no  such  thing  as  the  cell-theory  or  as 
physiological  chemistry ;  ontogeny  and  paleontology  were 
still  in  their  cradles.  Lamarck's  theory  of  descent  (1809) 
had  been  done  to  death,  like  his  fundamental  principle: 
"Life  is  only  an  elaborate  physical  phenomenon." 
Hence  we  can  easily  understand  how  physiologists 
acquiesced  in  the  vitalist  hypothesis  up  to  1833,  and 
supposed  the  wonders  of  life  to  be  enigmatic  phenomena 
that  escaped  physical  explanation. 

But  the  position  of  Palavitalism  changed  in  the  second 
third  of  the  nineteenth  century.  In  1833  appeared 
Johannes  Miiller's  classical  Manual  of  Human  Physiology, 
in  which  the  great  biologist  not  only  made  a  comparative 
study  of  the  vital  phenomena  in  man  and  the  animals, 
but  sought  to  provide  a  sound  basis  for  it  in  all  its 
sections  by  his  own  observations  and  experiments.     It 

48 


LIFE 

is  true  that  Miillcr  retained  to  the  last  (1858)  the 
current  idea  of  a  vital  force,  as  the  supreme  regulator  of 
all  the  vital  activities.  However,  he  did  not  regard  it  as 
a  metaphysical  principle  (like  Haller,  Kant,  and  their 
followers),  but  as  a  natural  force,  subject,  like  all  others, 
to  fixed  chemical  and  physical  laws,  and  subordinate  to 
the  whole.  In  his  comprehensive  study  of  every  single 
vital  function — the  organs  of  sense  and  the  nervous 
system,  metabolism  and  the  action  of  the  heart,  speech 
and  reproduction  —  Miiller  endeavored  above  all  to 
establish,  by  close  observation  of  the  facts  and  careful 
experiments,  the  regularity  of  the  phenomena,  and  to 
explain  their  development  by  a  comparison  of  the  higher 
and  lower  forms.  Hence  Johannes  Miiller  is  wrongly 
described — as  he  has  been  of  late — as  a  vitalist;  he  was 
rather  the  first  physiologist  to  provide  a  physical 
foundation  for  the  current  metaphysical  vitalism.  He 
really  gives  an  indirect  proof  of  the  reverse  theory,  as 
E.  Dubois-Reymond  rightly  observed  in  his  brilliant 
memorial  speech.  In  the  same  way  Schleiden  (1843)  cut 
the  ground  from  under  vitalism  in  botany.  By  his  cell- 
theory  (1838)  he  showed  the  unity  of  the  multicellular 
organism  to  be  the  resultant  of  the  functions  of  all  the 
cells  which  compose  it. 

The  physical  explanation  of  the  vital  processes  and 
the  rejection  of  Palavitalism  were  general  in  the  last 
third  of  the  nineteenth  century.  This  was  due  most 
of  all  to  the  great  advance  in  experimental  physiology, 
which  Carl  Ludwig  and  Felix  Bernard  led  as  regards 
the  animal  body,  and  Julius  Sachs  and  Wilhelm  Preyer 
for  the  plant.  While  these  and  other  physiologists 
used  the  remarkable  results  of  modern  physics  and 
chemistry  in  the  experimental  study  of  the  vital  func- 
tions, and  sought  to  detennine  their  complicated  course 
in  terms  of  mass  and  weight  and  formulate  their  dis- 
coveries as  mathematically  as  possible,  they  brought  a 
4  49 


THE    WONDERS    OF    LIFE 


great  number  of  the  wonders  of  life  under  the  same 
fixed  laws  that  were  recognized  in  the  physics  and 
chemistry  of  the  inorganic  world.  On  the  other  hand, 
vitalism  met  with  a  powerful  opponent  in  Charles 
Darwin,  who  solved,  by  his  theory  of  selection,  one  of 
the  most  obscure  biological  problems,  the  constantly 
repeated  question:  How  can  we  give  a  mechanical  ex- 
planation of  the  orderly  structures  of  the  living  being  ? 
How  was  this  ingenious  machine  of  the  animal  or  plant 
body  unconsciously  produced  by  natural  means,  without 
supposing  that  some  intelligent  artificer  or  creator  had 
deliberately  designed  and  produced  it? 

The  further  development  of  Darwin's  theory  of 
selection  in  the  last  four  decades,  and  the  increasing 
support  which  has  been  given  to  the  theory  of  descent 
in  the  great  advance  of  ontogeny,  phylogeny,  compara- 
tive anatomy,  and  physiology,  did  much  to  establish  the 
monistic  conception  of  life.  It  took  the  shape  more  and 
more  of  a  definite  anti- vitalism.  Hence  it  is  strange  to 
find  that  in  the  course  of  the  last  twenty  years  the  old 
vitalism  that  everybody  had  thought  dead  has  lifted  up 
its  head  once  more,  though  in  a  new  and  modified  form.^ 
This  modern  vitalism  comprises  two  essentially  different 
tendencies. 

The  partisans  of  the  modern  vital  force  are  divided 
into  two  groups,  which  may  be  designated  the  sceptical 
and  the  dogmatic.  Sceptical  Neovitalism  was  first 
formulated  by  Bunge,of  Basle  (1887),  in  the  introduction 
to   his  Manual  of  Physiological  Chemistry.     While  he 

^  This  refers  almost  entirely  to  Germany.  The  reader  will 
remember  that,  when  Lord  Kelvin  endeavored  to  make  the- 
osophic  capital  out  of  this  temporary  confusion  in  German 
science,  he  was  immediately  silenced  by  the  leading  biologists 
of  this  country,  Professor  E.  Ray-Lankester  (for  zoology), 
Sir  W.  T.  Thiselton-Dyer  (for  botany),  and  Sir  J.  Burdon- 
Sanderson  (for  physiology),  who  sharply  reiected  vitalism. — 
Trans. 

50 


LIFE 

granted  the  possibility  of  a  full  explanation  of  one  part 
of  the  vital  phenomena  by  mechanical  causes,  or  the 
physical  and  chemical  forces  of  lifeless  nature,  he  rejected 
it  for  the  other  half,  especially  for  psychic  activities. 
He  insists  that  the  latter  cannot  be  explained  mechani- 
cally, and  that  there  is  nothing  analogous  to  them  in 
inorganic  nature;  only  a  supra-mechanical  vital  force 
can  produce  them,  and  this  is  transcendental  and 
beyond  the  range  of  scientific  inquiry.  Much  the  same 
was  said  later  by  Rindfieisch  (1888),  more  recently  by 
Richard  Neumeister  in  his  Studies  of  the  Nature  of 
Vital  Phenomena  (1903),  and  by  Oscar  Hertwig  in  the 
lecture  on  "The  Development  of  Biology  in  the  Nine- 
teenth Century,"  which  he  delivered  at  Aachen  in 
1900. 

This  sceptical  Neovitalism  is  far  surpassed  by  the 
dogmatic  system,  the  chief  actual  representatives  of 
which  are  the  botanist  Johannes  Reinke  and  the  meta- 
physician Hans  Driesch.  The  vitalist  writings  of 
the  latter,  which  are  devoid  of  any  grasp  of  historical 
development,  have  gained  a  certain  vogue  through  the 
extraordinary  arrogance  of  their  author  and  the  obscurity 
of  his  mystic  and  contradictory  speculations.  Reinke,  on 
the  other  hand,  has  presented  his  transcendental  dualism 
in  clever  and  attractive  form  in  two  works  which  deserve 
notice  on  account  of  their  consistent  dualism.  In  the 
first  of  these,  The  World  as  Reality  (1899),  Reinke  gives 
us  "the  outline  of  a  scientific  theory  of  the  universe." 
The  second  work  (1901)  has  the  title.  Introduction  to 
Theoretical  Biolof^y.  The  two  works  have  the  same 
relation  to  each  other  as  my  Riddle  of  the  Universe  and  the 
present  supplementary  volume.  As  our  philosophic 
convictions  are  diametrically  opposed  in  the  main 
issues,  and  as  we  both  think  ourselves  consistent  in 
developing  them,  the  comparison  of  them  is  not  without 
interest  in  the  great  struggle  of  beliefs.     Reinke  is  an 

51 


THE    WONDERS    OF    LIFE 


avowed  supporter  of  dualism,  theism,  and  teleology. 
He  reduces  all  the  phenomena  of  life  to  a  supernatural 
miracle. 

Second   Table 

ANTITHESIS   OF   THE   MONISTIC   AND   DUALISTIC 
THEORIES    OF  ORGANIC   LIFE 


Monistic    Theory     of     Life 
(Biophysics) 

1.  The  phenomena  of  life  are 

merely  functions  of  plasm, 
determined  by  the  phys- 
ical, chemical,  and  mor- 
phological character  of  the 
living  matter. 

2.  The  energy  of  the  plasm  (as 

the  sum-total  of  the  forces 
which  are  connected  with 
the  living  matter)  is  sub- 
ject to  the  general  laws  of 
physics  and  chemistry. 

3 .  The  obvious  regularity  of  the 

vital  processes  and  the 
organization  they  produce 
are  the  outcome  of  natural 
evolution ;  their  physio- 
logical factors  (heredity 
and  adaptation)  are  sub- 
ject to  the  law  of  sub- 
stance. 

4.  All    the    various    functions 

have  thus  been  mechani- 
cally produced,  orderly 
structures  having  been 
created  by  adaptation  and 
transmitted  to  posterity 
by  heredity. 

5.  Nutrition  is  a  physico-chem- 

ical process,  the  metabo- 
lism of  which  has  an 
analogy  in  inorganic  ca- 
talysis. 

6.  Reproduction  is  a  mechan- 

ical consequence  of  trans- 
gressive  growth,  analo- 
gous to  the  elective  multi- 
plication of  crystals. 


DuALisTic    Theory    of    Life 
(Vitalism) 

1.  The  phenomena  of  life  are 

w^holly  or  partly  inde- 
pendent of  the  plasm,  and 
determined  by  a  special 
immaterial  force,  the  vital 
force   {vis  vitalis). 

2.  The  energy  of  the  plasm  is 

w^iolly  or  partly  subject 
to  the  immaterial  vital 
force,  which  controls  and 
directs  the  physical  and 
chemical  forces  of  the 
living  matter. 

3.  The  general  regularity  in  the 

organization  and  in  the 
vital  processes  it  accom- 
plishes is  the  outcome  of 
conscious  creation;  it  can 
only  be  explained  by  in- 
telligent immaterial  forces 
which  are  not  subject  to 
the  law  of  substance. 

4.  All  the  various  functions  of 

organisms  have  been  pro- 
duced by  design,  the 
historical  evolution  (or 
phyletic  transformation) 
being  directed  to  a  pre- 
conceived ideal  end. 

5.  Nutrition  is  an  inexplicable 

miracle  of  life,  and  cannot 
be  understood  by  chemical 
and  physical  processes. 

6.  Reproduction    is    an    inex- 

plicable miracle  of  life, 
without  any  analogy  in 
inorganic  nature. 


52 


LIFE 


ANTITHESIS    OF    THE    MONISTIC    AND    DUALISTIC 
THEORIES   OF   ORGANIC   LIFE— Cotttinned 


The  movement  of  orfj^anisms 
is,  in  every  form,  not 
essentially  different  from 
the  movements  of  inor- 
ganic dynamos. 

Sensation  is  a  general  form 
of  the  energy  of  substance, 
not  specifically  different 
in  sensitive  organisms  and 
irritable  inorganic  objects 
(such  as  powder,  dyna- 
mite). There  is  no  such 
thing  as  an  immaterial 
soul. 


7.  The  movement  of  organisms 

is  an  inexplicable  meta- 
ph3''sical  miracle  of  life, 
specifically  different  from 
all  inorganic  mov^ements. 

8.  The  sensation  of  organisms 

can  only  be  explained  by 
ascribing  a  soul  to  them, 
an  immaterial,  immortal 
being  that  only  dwells  for 
a  time  in  the  body.  After 
death  this  sj^irit  liv^es  an 
independent  life. 


Ill 

MIRACLES 

Miracle  and  natural  law — Belief  in  miracles  of  savages  (fetich- 
ism),  of  semi-civilized  (idolatry),  of  civilized  (theism), 
and  of  educated  people  (dualism) — Religious  belief  in 
miracles — Apostles'  Creed — Article  relating  to  creation — 
Article  relating  to  redemption — Article  relating  to  im- 
mortality— Philosophic  belief  in  miracles — Academic  think- 
ers and  Free-thinkers — Dualism  of  Plato  and  Kant — Belief 
in  miracles  in  the  nineteenth  century,  in  modern  meta« 
physics,  theology,  and  politics. 

IN  ordinary  parlance  the  word  "miracle  "  means  a  num- 
ber of  different  things.  We  say  a  phenomenon  is 
miraculous  or  wonderful  ^  when  we  cannot  explain  it  and 
trace  its  causes.  But  we  say  a  natural  object  or  a  work 
of  art  is  wonderful  when  it  is  unusually  beautiful  and 
imposing — when  it  passes  the  ordinary  limits  of  our 
experience.  In  this  work  I  do  not  take  the  word  in  this 
relative  sense,  but  in  the  absolute  sense  in  which  a 
phenomenon  is  said  to  transcend  the  limits  of  natural 
law  and  lie  beyond  the  range  of  rational  explanation. 
In  this  sense  it  means  the  same  as  "supernatural"  or 
"transcendental."  We  can  know  natural  phenomena 
by  our  reason  and  bring  them  within  our  cognizance. 
The  miraculous  can  only  be  accepted  on  faith. 

*  The  German  word  wunder  corresponds  equally  to  the 
English  "miracle"  and  "wonder."  It  has  seemed  necessary  to 
translate  it  "wonder"  in  the  title  of  the  work,  but  frequently 
as  "miracle"  in  this  chapter. — Trans. 

54 


M  I  R  A  C  L  E  wS 

The  belief  in  supernatural  miracles  is  in  contradiction 
to  pure  reason,  which  lays  the  foundations  of  all  science. 
Kant,  who  won  so  great  a  vogue  for  the  term  "pure 
reason,"  understood  by  this  originally  "reason  as  inde- 
pendent of  experience."  The  phrase  was  used  in  a 
narrower  sense  subsequently  to  express  independence  of 
dogma  and  prejudice,  as  the  base  of  pure  and  unprej- 
udiced science.  In  this  sense  we  oppose  pure  reason  to 
superstition. 

I  have  dealt  in  the  sixteenth  chapter  of  the  Riddle 
with  the  important  question  of  the  relations  of  knowledge 
and  faith.  But  I  must  return  to  the  vsubject  here,  as 
what  I  said  has  given  rise  to  a  good  deal  of  misunder- 
standing and  criticism.  I  by  no  means  claimed,  as  my 
opponents  allege,  to  "know  everything,"  or  to  have 
solved  every  problem.  In  fact,  I  said  repeatedly  that 
there  are  narrow  limits  to  our  knowledge,  and  always 
will  be.  I  had  also  expressly  stated  that  the  irresistible 
impulse  to  learn  in  the  intelligent  man,  or  reason's 
constant  demand  to  know  causes,  presses  us  to  fill  up  the 
gaps  in  our  knowledge  by  faith.  But  I  had  at  the  same 
time  pointed  out  the  contrast  between  scientific  (natural) 
and  religious  (supernatural)  faith.  The  one  leads  us  to 
form  hypotheses  and  theories;  the  other  ends  in  myths 
and  superstition.  vScientific  faith  fills  the  gaps  in  our 
knowledge  of  natural  law  with  temporary  hypotheses; 
but  mystic  religious  faith  contradicts  natural  law,  and 
transcends  its  limits  in  the  form  of  a  belief  in  miracles. 

The  great  triumph  of  the  progress  of  science  in  the 
nineteenth  century,  its  theoretical  value  in  the  formation 
of  a  rational  philosophy  of  life,  and  its  practical  value  on 
the  various  sides  of  modern  civilization,  consist,  above 
all,  in  the  absolute  recognition  of  fixed  natural  laws. 
That  relation  of  things  to  each  other,  which  we  call 
causation,  makes  it  possible  for  us  to  understand  and 
explain  facts.     We  feel  that  our  thirst  for  a  knowledge 

55 


THE    WONDERS    OF    LIFE 

of  the  causes  of  things  is  contented  when  science  points 
out  the  "sufficient  reason"  of  them.  In  the  whole 
province  of  inorganic  cosmology  natural  law  is  now 
generally  recognized  to  be  all-powerful;  in  astronomy, 
geology,  physics,  and  chemistry  all  phenomena  are 
reduced  to  fixed  laws,  and  in  the  long-run  to  the  all- 
embracing  law  of  substance,  the  great  law  of  the  conser- 
vation of  matter  and  force  {Kiddle,  chapter  xii.). 

It  is  otherwise  in  biology,  or  the  organic  section  of 
cosmology.  Here  we  still  find  miracles  set  up  in  opposi- 
tion to  the  law  of  substance,  and  the  transgression  of 
natural  laws  by  supernatural  forces.  The  behef  in 
miracles  of  this  kind,  which  pure  reason  calls  supersti- 
tion, is  still  very  w^idespread  —  much  more  prevalent 
than  is  usuahy  thought.  For  my  part,  I  hold  that 
superstition  and  unreason  are  the  worst  enemies  of  the 
human  race,  while  science  and  reason  are  its  greatest 
friends.  Hence  it  is  our  duty  and  task  to  attack  the 
belief  in  miiacles  wherever  we  find  it,  in  the  interest  of 
the  race.  We  have  to  prove  that  the  reign  of  natural 
law  extends  over  the  whole  world  of  phenomena  as 
far  as  we  can  reach  it.  A  general  survey  of  the  his- 
tory of  faith  on  the  one  hand  and  of  science  on  the 
other  clearly  shows  that  the  advance  of  the  latter  has 
always  been  accompanied  by  an  increasing  knowledge  of 
fixed  natural  laws  and  the  shrinking  of  superstition  into 
Jan  ever-lessening  area.  To-day  we  convince  ourselves 
of  this  by  an  impartial  examination  of  mental  culture  at 
the  various  stages  of  civilization.  For  this  purpose  I 
take  the  four  chief  stages  of  mental  development  which 
Fritz  Schultze  has  given  in  his  Physiology  of  Uncivilized 
Races,  and  Alexander  Sutherland  in  his  work,  On  the 
Origin  and  Growth  of  the  Moral  Instinct:  i,  savages; 
2,  barbarians;  3,  civilized  races;  4,  ediicated  races  {cf. 
chapter  i.). 

The   mental   life   of   savages   rises   Httle   above   that 

56 


MIRACLES 

of  the  higher  mammals,  especially  the  apes,  with  which 
they  are  genealogically  connected.  Their  whole  interest 
is  restricted  to  the  physiological  functions  of  nutrition 
and  reproduction,  or  the  satisfaction  of  hunger  and  thirst 
in  the  crudest  animal  fashion.  Without  fixed  habitation, 
constantly  struggling  for  existence,  they  live  on  the  raw 
produce  of  nature — fruits,  the  roots  of  wild  plants,  and 
the  animals  they  fish  in  the  water  or  catch  on  land. 
Their  intelligence  moves  within  the  narrowest  bounds, 
and  one  can  no  more  (or  no  less)  speak  of  their  reason 
than  of  that  of  the  more  intelligent  animals.  Of  art 
and  science  there  is  no  question.  Their  impulse  to  dis- 
cover causes  is  satisfied  with  the  simplest  association  of 
phenomena  which  have  a  merely  external  connection, 
but  no  intimate  relation  to  each  other.  Thus  arises 
their  fetichisin,  that  irrational  trust  in  fetiches  which 
Fritz  Schultze  has  traced  to  four  distinct  causes:  their 
false  estimate  of  the  value  of  an  object,  their  anthropo- 
morphic conception  of  nature,  the  imperfect  association 
of  their  ideas,  and  the  strength  of  their  emotions,  espe- 
cially hope  and  fear.  Any  favorite  object,  a  stone  or  a 
bone,  may  work  miracles  as  a  fetich  and  exercise  all 
kinds  of  good  or  evil  influence,  and  is  therefore  honored, 
feared,  and  worshipped.  At  first  the  worship  was  paid 
to  the  invisible  spirit  that  dwelt  in  the  particular  object; 
but  it  was  often  transferred  afterwards  to  the  dead  object 
itself.  Among  the  different  savage  races  the  belief  in 
fetiches  presents  a  number  of  stages,  corresponding  to 
the  beginnings  of  reason.  The  lowest  stage  is  found  in 
the  lowest  races,  such  as  the  Veddahs  of  Ceylon,  the 
Andaman  Islanders,  Bushmen,  and  Akkas  (of  New 
Guine).  A  somewhat  higher  stage  is  met  in  the  middle 
races  (Australian  negroes,  Tasmanians,  Hottentots,  and 
Tierra  del  Fuegians);  and  a  still  higher  intellectual 
development  is  shown  by  the  next  group  (most  of  the 
Indians  of   North   and   South   America,   the  aboriginal 

57 


THE    WONDERS    OF    LIFE 

inhabitants  of  India,  etc.).  Modern  comparative  ethnog- 
raphy and  evolution  and  prehistoric  and  anthropo- 
logical research  have  shown  us  that  our  own  ancestors, 
ten  thousand  and  more  years  ago,  were  (like  the  pre- 
historic ancestors  of  all  races  of  men)  savages,  and  that 
their  earliest  belief  in  miracles  was  a  crude  fetichism. 

By  barbarians  we  understand  the  races  that  are  found 
between  savage  and  civilized  peoples.  They  show  the 
first  beginnings  of  civilization,  and  are  superior  to 
savages  chiefly  in  the  possession  of  agriculture  and  the 
keeping  of  cattle.  They  make  a  provident  use  of  the 
productive  forces  of  organic  nature,  artificially  produce 
large  quantities  of  food,  and  are  thus  enabled  by  the 
abundance  of  food  to  turn  their  minds  to  other  interests. 
We  find  that  they  have  the  rudiments  of  art  and  science. 
Their  religion  does  not  at  first  rise  much  above  fetichism, 
but  soon  reaches  the  stage  of  animism,  lifeless  objects 
in  nature  being  credited  with  souls.  Worship  is  no 
longer  paid  to  favorite  dead  objects  (stones,  bones,  etc.), 
but  generally  to  living  things,  trees  and  animals,  and 
especially  to  images  of  gods  which  have  the  form  of 
animals  or  men,  and  are  believed  to  possess  souls.  As 
demons  or  spirits,  these  have  a  great  influence  on  the 
fortunes  of  men.  At  first  this  soul  is  conceived  to  be 
purely  material;  it  disappears  at  the  death  of  the  body 
and  lives  apart.  As  the  breathing  and  the  beat  of  the 
pulse  and  heart  cease  when  a  man  dies,  the  seat  of  the 
soul  is  thought  to  be  the  lungs,  heart,  or  some  other 
part  of  the  body.  The  idea  of  the  immortality  of  the 
soul  takes  on  innumerable  forms  among  them,  like  the 
belief  in  the  miracles  which  are  worked  by  the  gods, 
demons,  spirits,  etc.  Evolution  again  points  out  a  long 
gradation  of  forms  of  faith,  if  we  compare  the  lower, 
middle,  and  higher  races. 

^Civilized  races  are  distinguished  from  barbaric  by  the 
formation  of  states  with  an  extensive  division  of  labor. 

58 


MIRACLES 

The  social  organism  is  not  only  larger  and  more  power- 
ful, but  is  capable  of  a  greater  variety  of  achievements, 
the  functions  of  the  various  states  and  classes  of  work- 
ers being  more  highly  differentiated  and  mutually  com- 
plementary (like  the  cells  and  tissues  in  the  higher 
animal  body  of  the  metazoa).  Nutrition  is  easier  and 
more  luxurious.  Art  and  science  are  well  developed.  A 
great  advance  is  seen  in  regard  to  reHgion,  the  numerous 
gods  being  generally  conceived  as  manlike  spirits,  and 
finally  subordinated  to  a  chief  god.  The  belief  in  miracles 
flourishes  greatly  in  poetry;  in  philosophy  it  is  more 
and  more  restricted.  In  the  end,  the  working  of  mir- 
acles is  limited  monotheistically  to  one  god,  or  to  his 
priests  and  other  men  to  whom  he  communicates  the 
power. 

Modern  civilization  in  the  narrower  sense,  as  a  con- 
trast to  the  older  civilization,  opens,  in  my  opinion,  at 
the  beginning  of  the  sixteenth  century.  At  that  time 
took  place  some  of  the  greatest  achievements  of  human 
thought  among  civilized  peoples,  and  these  broke  the 
chains  of  tradition  and  gave  a  fresh  impetus  to  progress. 
Men's  own  mental  outlook  was  widened  by  the  system  of 
Copernicus  and  the  Reformation  freed  them  from  the 
yoke  of  the  papacy.  Shortly  before,  the  discovery  of  the 
New  World  and  the  circumnavigation  of  the  globe  had 
convinced  men  of  the  rotundity  of  the  earth;  geography, 
natural  history,  medicine,  and  other  sciences  gained 
inspiration  and  independence;  printing  and  engraving 
provided  an  important  means  of  spreading  the  new 
knowledge.  This  fresh  impetus  was  chiefly  of  service 
to  philosophy,  which  now  more  and  more  rejected  the 
dictation  of  the  Church  and  superstition;  though  it  was 
far  from  casting  off  the  fetters  altogether.  This  was  not 
generally  possible  until  the  nineteenth  century,  when 
empirical  science  assumed  an  enormous  importance,  and 
in  the  ensuing  period  of  speculation  the  physical  con- 

59 


THE    WONDERS    OF    LIFE 

ception  of  the  world  gained  more  and  more  on  the 
metaphysical.  Pure  knowledge,  thus  grounded  on 
science,  entered  into  sharper  conflict  than  ever  with 
religious  faith.  If,  as  in  the  preceding  caseS;  we  distin- 
guish three  stages  in  the  development  of  modern 
civilization,  we  recognize  the  progressive  liberation  from 
superstition  by  scientific  knowledge. 

When  we  compare  the  higher  forms  of  religion  of 
civilized  nations  we  find  the  same  emotional  cravings 
and  thought-processes  constantly  recurring,  and  the 
belief  in  miracles  developing  in  much  the  same  way. 
The  three  founders  of  the  great  monotheistic  Mediter- 
ranean religion — Moses,  Christ,  and  Mohammed — were 
equally  regarded  as  wonder-working  prophets,  having 
direct  intercourse  with  God  in  virtue  of  their  special 
gifts,  and  transmitting  his  commands  to  men  in  the 
shape  of  laws.  The  extraordinary  authority  they  enjoy, 
which  has  given  so  much  prestige  to  the  religions  they 
founded,  is  grounded  for  ordinary  people  on  their  mi- 
raculous powers — the  healing  of  the  sick,  the  raising 
of  the  dead,  the  expiilsion  of  devils,  and  so  on.  If  we 
examine  the  miracles  of  Christ  as  they  are  given  in  the 
gospels,  they  run  counter  to  the  laws  of  nature  and 
rational  explanation  just  in  the  same  way  as  the  similar 
miracles  of  Buddha  and  Brahma  in  Hindoo  mythology, 
or  of  Mohammed  in  the  Koran.  The  same  must  be  said 
of  the  belief  in  the  miracle  of  the  bread  and  wine  in  the 
Lord's  supper,  and  the  hke.  The  Creed  which  was 
probably  drawn  up  by  the  leaders  of  the  Christian 
.communities  of  the  second  century,  and  received  its 
final  and  present  form  in  the  Church  of  South  Gaul  in 
the  fourth  and  fifth  centuries,  has  been  obligatory  for 
Christians  for  fifteen  hundred  years,  and  recognized 
by  both  Church  and  State  as  compulsory.  This  Apostles' 
Creed  was  also  recognized  in  Luther's  catechismi  to  be 
fundamental,  and  is  taught  in  all  Protestant  and  Roman 

60 


MIRACLES 

Catholic  schools  (though  not  in  the  Greek  Catholic)  as 
the  foundation  of  religious  instruction.  This  extraor- 
dinary prestige  of  the  Apostles'  Creed,  and  its  great 
influence  on  the  education  of  the  young,  no  less  than 
its  glaring  inconsistency  with  rational  knowledge,  compel 
us  to  devote  a  few  pages  to  a  critical  examination  of  its 
three  articles. 

The  first  article  of  the  Creed  deals  with  creation,  and 
runs:  "I  believe  in  God,  the  Father  Almighty,  Creator 
of  heaven  and  earth."  The  modern  science  of  evolution 
has  shown  that  there  never  Avas  any  such  creation,  but 
that  the  universe  is  eternal  and  the  law  of  substance  all- 
ruling.  God  himself  is  anthropomorphically  conceived 
as  an  "Almighty  Creator"  and  the  Father  of  man; 
heaven  (in  the  sense  of  the  geocentric  system)  is  imag- 
ined as  a  great  blue  vault  spanning  the  earth.  The  no- 
tion of  this  "personal  God"  as  an  intelligent,  immaterial 
being,  creating  the  material  world  out  of  nothing, 
is  wholly  irrational  and  meaningless.  That  Luther 
accepted  this  childish  and  scientifically  worthless  idea  is 
clear  from  his  commentary  on  the  first  article — "  What  is 
that?" 

The  second  article  of  the  Creed  deals  with  the  dogma 
of  salvation  in  the  following  words:  "I  believe  in  Jesus 
Christ,  his  only  son,  our  Lord,  who  was  conceived  of  the 
Holy  Ghost,  born  of  the  Virgin  Mary,  suffered  under 
Pontius  Pilate,  was  crucified,  dead,  and  buried,  descend- 
ed into  hell,  on  the  third  day  rose  again  from  the  dead, 
ascended  into  heaven,  sitteth  at  the  right  hand  of  God, 
the  Father  Almighty,  whence  he  will  come  to  judge  the 
living  and  the  dead."  As  these  dogmas  of  the  second 
article  contain  the  chief  points  of  the  redemption  theory, 
and  are  still  treasured  by  millions  of  educated  people,  it 
is  necessary  to  point  out  their  flagrant  opposition  to  pure 
reason.  The  chief  evil  of  such  creeds  is  that  children, 
who  are  yet  incapable  of  reflecting,  are  forced  to  learn 

6i 


THE    WONDERS    OF    LIFE 

them  by  heart.  They  then  remain  unchallenged  as  re- 
vealed truths. 

The  myth  of  the  conception  and  birth  of  Jesus  Christ 
is  mere  fiction,  and  is  at  the  same  stage  of  superstition 
as  a  hundred  other  myths  of  other  religions.  Of  the 
three  persons  who  are  mysteriously  blended  in  the  triune 
God,  the  son  Christ  is  supposed  to  be  begotten  by  both 
Father  and  Holy  Ghost,  parthenogenetically  through  the 
Virgin  Mary.  I  have  dealt  with  the  physiology  of 
parthenogenesis  in  the  seventeenth  chapter  of  the  Riddle. 
The  curious  adventures  of  Christ  after  his  death,  the 
descent  into  hell,  resurrection,  and  ascension,  are  also 
fantastic  myths  due  to  the  narrow  geocentric  ideas  of  an 
uneducated  people.  Troelslund  has  admirably  explain- 
ed the  strong  influence  they  have  had  in  his  interesting 
book,  The  Idea  of  Heaven  and  of  the  World}  The  idea 
of  the  "last  judgment,"  with  Christ  sitting  on  the  right 
hand  of  the  Father,  as  many  famous  mediaeval  pictures 
represent  (notably  Michael  Angelo's  in  the  Sistine  Chapel 
at  the  Vatican),  is  another  outcome  of  a  thoroughly 
childish  and  anthropomorphic  attitude. 

It  is  remarkable  that  this  second  article  of  the  Creed 
says  nothing  about  "redemption,"  which  forms  its  head- 
ing [in  Germany].  Luther  has  dealt  with  it  in  his 
commentary.  Christ  is  believed  to  have  suffered  a 
painful  death,  like  many  thousand  other  martyrs,  for  his 
conviction  of  the  truth  of  his  faith  and  teaching — which 
reminds  one  of  the  more  than  a  hundred  thousand  men 
who  were  done  to  death  by  the  Inquisition  and  in  the 
religious  wars  of  the  Middle  Ages;  but  not  one  of  the 

^  The  English  reader  may  usefully  be  reminded  that  Professor 
Loofs,  Haeckel's  chief  critic,  and  one  of  the  foremost  German 
theologians,  rejects  these  articles  of  the  Creed  no  less  than 
Haeckel  does.  A  glance  at  the  pertinent  articles  in  the  En- 
cyclopaedia Biblica  will  show  how  widely  theologians  now  discard 
these  beliefs. — Trans. 

62 


MIRACLES 

millions  of  ministers  who  preach  on  it  every  Sunday 
seems  to  have  shown  a  rational  causal  connection  of  this 
death  with  the  alleged  redemption  from  sin  and  death. 
The  whole  of  this  story  of  redemption  has  sj^rung  from 
the  primitive,  obscure,  ethical  ideas  of  uneducated  races, 
especially  the  crude  belief  in  the  propitiatory  power  of 
human  sacrifice.  It  has  no  practical  moral  value  except 
for  those  who  believe  in  personal  immortality — a  scien- 
tifically untenable  dogma.  Whoever  builds  on  this  empty 
promise  of  a  better  life  beyond  may  soothe  himself  with 
this  hope,  and  reconcile  himself  to  the  thousand  ills  and 
defects  of  this  world.  But  the  man  who  studies  this 
life  as  it  really  is  will  not  find  that  the  belief  in  re- 
demption has  brought  any  real  improvement.  Want 
and  misery  and  sin  are  as  prevalent  as  ever;  indeed, 
our  modern  civilization  has,  in  many  respects,  increased 
them. 

The  third  and  last  article  of  the  Apostles'  Creed  runs: 
"I  believe  in  the  Holy  Ghost,  the  holy  Catholic  Church, 
the  communion  of  saints,  the  forgiveness  of  sins,  the 
resurrection  of  the  body,  and  life  everlasting."  In  the 
curious  commentary  that  Luther  made  on  this  article  in 
his  catechism,  he  said  that  "man  cannot  believe  of  his 
own  reason  in  Jesus  Christ " — which  is  very  true — but  the 
Holy  Ghost  must  lead  him  thereto  with  his  grace;  but 
how  the  third  person  of  the  Trinity  effects  this  enlighten- 
ment and  sanctification  he  did  not  explain.  What  is 
meant  by  the  "communion  of  saints"  and  the  "holy 
Catholic  Church"  must  be  gathered  in  the  light  of  their 
history — especially  the  history  of  Romanism.  This  most 
powerful  and  still  influential  section  of  the  Christian 
Church,  which  especially  claims  the  title  of  Catholic  and 
"the  one  ark  of  salvation,"  is  really  a  most  pitiful 
caricature  of  pure  primitive  Christianity.  It  has,  with 
consummate  skill,  succeeded  in  preaching  the  beneficent 
teaching  of  Christ  in  theory  and  doing  just  the  opposite 

63 


THE    WONDERS    OF    LIFE 

in  practice;  we  need  only  recall  the  Inquisition,  the  dark 
history  of  the  Middle  Ages,  and  the  political  hierarchy 
which  still  dominates  so  much  of  civilization. 

However,  by  far  the  most  important  clause  in  the 
third  article  is  the  final  expression  of  belief  in  "the 
resurrection  of  the  body  and  life  everlasting."  That  this 
greatest  "wonder  of  life"  was  originally  conceived  in  a 
purely  material  form  is  evident  from  thousands  of 
pictures  in  which  famous  painters  have  realistically 
depicted  the  resurrection  of  the  dead,  the  aerial  flight  of 
the  happy  souls  of  the  blessed,  and  the  torments  of  the 
damned  in  hell.  It  is  thus  conceived  still  by  the  majority 
of  believers  who  take  eternal  life  to  be  an  "enlarged  and 
improved  edition"  of  life  here  below.  This  is  equally 
true  of  Christian  and  Mohammedan  pictures  and  of  the 
athanatist  ideas  that  prevailed  in  other  religions  long 
before  Christ  was  born,  even  of  the  first  rudiments  of  the 
belief  in  primitive  races.  As  long  as  the  geocentric 
theory  prevailed,  and  the  heavens  were  thought  to  be  a 
sort  of  blue  glass  bell,  illumined  by  thousands  of  little 
stars  and  the  lamp  of  the  sun,  arching  like  a  vault  over 
the  flat  earth,  and  the  fires  of  hell  burned  in  the  cellars 
below,  this  barbaric  notion  of  a  resurrection  of  the  body 
and  a  last  judgment  could  easily  be  maintained.  But 
its  roots  were  destroyed  when  Copernicus  refuted  the 
geocentric  theory  in  1545 ;  and  athanatism  became  quite 
untenable  when  Darwin  shattered  the  dogmia  of  an- 
thropocentricism.  Not  only  the  crude  older  materialistic 
idea  of  eternal  life,  but  also  the  refined  new  spiritualistic 
version,  has  been  rendered  untenable  by  the  progress  of 
science  in  the  nineteenth  century.  I  have  shown  this  in 
the  eleventh  chapter  of  the  Riddle,  v/hich  closes  with  the 
words:  "If  we  take  a  comprehensive  glance  at  all  that 
modern  anthropology,  x^s^^chology,  and  cosmology  teach 
with  regard  to  athanatism,  we  are  forced  to  this  definite 
conclusion.     The  belief  in  the  immortality  of  the  human 

64 


MIRACLES 

soul  is  in  hopeless  contradiction  with  the  most  solid 
empirical  truths  of  modern  science."^ 

The  great  influence  which  has  been  exercised  on 
civilized  nations  by  the  Christian  beliefs,  supported  by 
the  practical  exigencies  of  the  state,  for  thousands  of 
years,  was  chiefly  seen  in  the  crude  superstition  of  the 
mass  of  the  people.  Confessions  of  faith  became  as 
much  a  matter  of  routine  as  the  latest  fashion  in  dress  or 
the  latest  custom,  etc.  But  even  the  majority  of  the 
philosophers  were  more  or  less  subordinated  to  the  in- 
fluence. It  is  true  that  a  few  great  thinkers  freed  them- 
selves by  the  use  of  pure  reason  at  an  early  date  from  the 
prevalent  superstition,  and  framed  systems  apart  from 
tradition  and  the  priests.  But  most  philosophers  could 
not  rise  to  the  altitude  of  these  brave  Free-thinkers ;  they 
remained  "school-men "  in  the  literal  sense,  dependent  on 
the  dictation  of  authority,  the  traditions  of  the  school, 
and  the  dogmas  of  the  Church.  Philosophy  was  the 
"handmaid"  of  theology  and  ecclesiasticism.  If  we 
examine  the  history  of  philosophy  in  this  light,  we  find 
in  it  a  struggle  for  twenty-five  hundred  years  between 
two  great  tendencies — the  dualism  of  the  majority  (with 
theological  and  mystic  leanings)  and  the  monism  of  the 
minority  (with  rationahstic  and  naturahstic  disposition). 

Especially  notable  are  those  great  Free-thinkers  of 
classic  antiquity  who  taught  a  monistic  view  of  life  in  the 
sixth  century  before  Christ — the  Ionic  natural  philoso- 
phers, Thales,  Anaximander,  and  Anaximenes;  and  a 
little  later,  Heraclitus,  Empedocles,  and  Democritus. 
They  made  the  first  thorough  attempt  to  explain  the 
world  on  rational  principles,  independently  of  all  mytho- 
logical   tradition    and    theological    dogmas.     However, 

*  Compare  the  opinion  of  the  distinguished  American  psy- 
chologist, Mimsterberg  "  Science  opposes  to  any  doctrine  of 
individual  immortality  an  unbroken  and  impregnable  barrier" 
{Psychology  and  Life,  p.  85). — Trans. 

5  65 


THE    WONDERS    OF    LIFE 

these  remarkable  efforts  to  found  a  primitive  monism, 
which  found  so  finished  an  expression  in  the  De  rerum 
natiira  of  the  great  poet-philosopher,  Lucretius  Carus 
(98-54  B.C.),  were  shortly  thrust  out  by  the  spread — 
through  Plato's  curious  dualism — of  the  belief  in  the 
immortality  of  the  soul  and  the  transcendental  world  of 
ideas. 

The  Eleatics,  Parmenides  and  Zeno,  had  foreshadowed 
in  the  fifth  century  the  division  of  philosophy  into  two 
branches;  but  Plato  and  his  pupil  Aristotle  (in  the 
fourth  century  b.c.)  succeeded  in  gaining  general  accept- 
ance for  this  dualism  and  antithesis  of  physics  and  meta- 
physics. Physics  devoted  itself  on  the  ground  of  experi- 
ence to  the  study  of  the  phenom.ena  of  things,  leaving 
their  real  essences  (or  noumena)  that  lay  behind  the 
phenomena  to  metaphysics.  These  inner  eSvSences  are 
transcendental  and  inaccessible  to  empirical  research; 
they  form  the  metaphysical  world  of  eternal  ideas,  which 
is  independent  of  the  real  world,  and  has  its  highest 
unity  in  God,  as  the  Absolute.  The  soul,  an  eternal  idea 
that  dwells  for  a  time  in  the  passing  human  body,  is 
immortal.  This  consistent  dualism  of  Plato's  system, 
with  its  sharp  antithesis  of  this  world  and  the  next,  of 
body  and  soul,  of  world  and  God,  is  its  chief  character- 
istic. It  became  all  the  more  influential  when  Plato's 
pupil  Aristotle  blended  it  with  his  empirical  metaphysics, 
based  on  ample  scientific  experience,  and  pointed  out  the 
idea  in  the  entelechy,  or  purposively  acting  principle,  of 
every  being;  and  especially  when  Christianity  (three 
hundred  years  afterwards)  found  in  this  dualism  a 
welcome  philosophic  support  of  its  own  transcendental 
tendency. 

In  the  course  of  the  thousand  vears  which  historians 
call  the  Middle  Ages,  and  which  are  usually  dated  from 
the  fall  of  the  Roman  Empire  (476)  to  the  discovery  of 
America    (1492),    the    superstition    of    civilized    races 

66 


MIRACLES 

reached  its  highest  development.  The  authority  of 
Aristotle  was  paramount  in  philosophy;  it  was  used  by 
the  dominant  Church  for  its  own  purposes.  But  the 
influence  of  the  Christian  faith,  with  all  the  gay  color- 
ing which  the  fairy  -  tales  of  the  Bible  added  to  its 
structure  of  dogmas,  was  seen  much  more  in  practical 
life.  In  the  foreground  of  belief  were  the  three  central 
dogmas  of  metaphysics,  to  which  Plato  had  first  given 
complete  expression — the  personal  God  as  creator  of  the 
world,  the  immortality  of  the  soul,  and  the  freedom  of 
the  human  will.  As  Christianity  laid  the  greatest 
theoretical  stress  on  the  first  two  dogmas  and  the 
greatest  practical  stress  on  the  third,  metaphysical 
dualism  soon  prevailed  on  all  sides.  Especially  inimical 
to  scientific  inquiry  was  the  Christian  contempt  of  nature 
and  its  belittlement  of  earthly  life  in  view  of  the  eternal 
life  to  come.  As  long  as  the  light  of  philosophical 
criticism  in  any  form  was  extinguished,  the  flower- 
garden  of  religious  poetry  flourished  exceedingly  and  the 
idea  of  miracle  was  taken  as  self-evident.  We  know 
what  the  practical  result  of  this  superstition  was  from 
the  ghastly  history  of  the  Middle  Ages,  with  its  In- 
quisition, religious  wars,  instruments  of  torture,  and 
drowning  of  witches.  In  the  face  of  the  current  en- 
thusiasm for  the  romantic  side  of  mediasvalism,  the 
Crusades  and  Church  art,  we  cannot  lay  too  much  stress 
on  these  dark  and  bloody  pages  of  its  chronicles. 

An  impartial  study  of  the  immense  progress  made  by 
science  in  the  course  of  the  nineteenth  century  shows 
convincingly  that  the  three  central  metaphysical  dogmas 
established  by  Plato  have  become  untenable  for  pure 
reason.  Our  clear  modern  insight  into  the  regularity 
and  causative  character  of  natural  processes,  and  espe- 
cially our  knowledge  of  the  universal  reign  of  the  law  of 
substance,  are  inconsistent  with  belief  in  a  personal 
God,  the  immortality  of  the  soul,  and  the  freedom  of  the 

67 


THE    WONDERS    OF    LIFE 

will.  If  we  find  this  threefold  superstition  still  widely 
prevalent,  and  even  retained  by  academic  philosophers 
as  an  unshakable  consequence  of  "critical  philosophy," 
we  must  trace  this  remarkable  fact  chiefly  to  the  great 
prestige  of  Immanuel  Kant.  His  so  -  called  critical 
system — really  a  hybrid  product  of  the  crossing  of  pure 
reason  with  practical  superstition — has  enjoyed  a  greater 
popularity  than  any  other  philosophy,  and  we  must  stop 
to  consider  it  for  a  moment. 

I  have  described  in  chapters  xiv.  and  xx.  of  the  Riddle 
the  profound  opposition  between  my  monistic  system 
and  Kant's  dualistic  philosophy.  In  the  appendix  to 
the  popular  edition,  especially,  I  have  pointed  out  the 
glaring  contradictions  of  his  system,  which  other  philos- 
ophers have  often  detected  and  criticised.  Whenever 
there  is  question  of  his  teaching  one  must  ask:  "Which 
Kant  do  you  mean  ?  Kant  I . ,  the  founder  of  the  raonistic 
cosmogony,  the  critical  formulator  of  pure  reason;  or 
Kant  II.,  the  author  of  the  dualistic  criticism  of  judg- 
ment, the  dogmatic  discoverer  of  practical  reason  ?"  These 
contradictions  are  partly  due  to  the  psychological  meta- 
morphoses which  Kant  underwent  (Riddle,  chapter  vi.), 
partly  to  the  perennial  conflict  between  his  scientific 
bias  towards  a  mechanical  explanation  of  this  world  and 
his  religious  craving  (an  outcome  of  heredity  and  educa- 
tion) and  mystic  belief  in  a  life  beyond.  This  culminates 
in  the  distinction  between  the  world  of  sense  and  the 
world  of  spirit.  The  sense  world  {mnndtis  sensibilis) 
lies  open  to  our  senses  and  our  intellect,  and  is  em- 
pirically knowable  within  certain  limits.  But  behind  it 
there  is  the  spiritual  world  (mundiis  intelligihilis)  of 
which  we  know,  and  can  know,  nothing;  its  existence  (as 
the  thing  in  itself)  is,  however,  assured  by  our  emotional 
needs.  In  this  transcendental  world  dwells  the  power 
of  mysticism. 

It  is  said  to  be  the  chief  merit  of  Kant's  system  that 

68 


MIRACLES 

he  first  clearly  stated  the  problem:  "How  is  knowledge 
possible?"  In  trying  to  solve  this  jjroblem  introspec- 
tively,  by  a  subtle  analysis  of  his  own  mental  activity, 
he  reached  the  conviction  that  the  most  important  and 
soundest  of  all  knowledge — namely,  mathematical — con- 
sists of  synthetic  a  priori  judgments,  and  that  pure 
science  is  only  possible  on  condition  that  there  are  strict 
a  priori  ideas,  independent  of  all  experience,  without 
a  posteriori  judgments.  Kant  regarded  this  highest 
faculty  of  the  human  mind  as  innate,  and  made  no 
inquiry  into  its  development,  its  physiological  mech- 
anism, and  its  anatomic  organ,  the  brain.  Seeing  the 
very  imperfect  knowledge  which  human  anatomy  had  of 
the  complicated  structure  of  the  brain  at  the  beginning  of 
the  nineteenth  century,  it  was  impossible  to  have  at 
that  time  a  correct  idea  of  its  physiological  function. 

What  seems  to  us  to-day  to  be  an  innate  capacity,  or 
an  a  priori  quality,  of  our  phronema,  is  really  a  phylo- 
genetic  result  of  a  long  series  of  brain-adaptations, 
formed  by  a  posteriori  sense-perceptions  and  experi- 
ences. 

Kant's  much-lauded  critical  theory  of  knowledge  is 
therefore  just  as  dogmatic  as  his  idea  of  "the  thing  in 
itself,"  the  unintelligible  entity  that  lurks  behind  the 
phenomena.  This  dogma  is  erroneously  built  on  the 
correct  idea  that  our  knowledge,  obtained  through  the 
senses,  is  imperfect;  it  extends  only  so  far  as  the  specific 
energy  of  the  senses  and  the  structure  of  the  phronema 
admit.  But  it  by  no  means  follows  that  it  is  a  mere 
illusion,  and  least  of  all  that  the  external  world  exists 
only  in  our  ideas.  All  sound  men  believe,  when  they 
use  their  senses  of  touch  and  space,  that  the  stone  they 
feel  fills  a  certain  part  of  space,  and  this  space  does 
really  exist.  When  all  men  who  can  see  agree  that  the 
sun  rises  and  sets  every  day,  this  proves  a  relative 
motion  of  the  two  heavenly  bodies,   and  so  the  real 

69 


THE    WONDERS    OF    LIFE 

existence  of  time.  Space  and  time  are  not  merely 
necessary  forms  of  intuition  for  human  knowledge,  but 
real  features  of  things,  existing  quite  independently  of 
perception. 

The  increasing  recognition  of  fixed  natural  laws  which 
accompanied  the  growth  of  science  in  the  nineteenth 
century  was  bound  to  restrict  more  and  more  the  blind 
faith  in  miracles.  There  are  three  chief  reasons  why  we 
find  this,  nevertheless,  still  so  prevalent — the  continued 
influence  of  dualistic  metaphysics,  the  authority  of  the 
Christian  Church,  and  the  pressure  of  the  modern  state 
in  allying  itself  with  the  Church.  These  three  strong 
bulwarks  of  superstition  are  so  hostile  to  pure  reason 
and  the  truth  it  seeks  that  we  must  devote  special 
attention  to  them.  It  is  a  question  of  the  highest 
interests  of  humanity.  The  struggle  against  supers ti- 
ption  and  ignorance  is  a  fight  for  civilization.  Our 
modern  civilization  will  only  emerge  from  it  in  triumph, 
and  we  shall  only  eliminate  the  last  barbaric  features 
from  our  social  and  political  life,  when  the  light  of  true 
knowledge  has  driven  out  the  belief  in  miracles  and  the 
prejudices  of  dualism. 

The  remarkable  history  of  philosophy  in  the  nineteenth 
century,  which  has  not  yet  been  written  with  complete 
impartiality  and  knowledge,  shows  us  in  the  first  place 
an  ever-increasing  struggle  between  the  rising  young 
sciences  and  the  paramount  authority  of  tradition  and 
dogma.  In  the  first  half  of  the  century  the  various 
branches  of  biology  made  progress  without  coming  into 
direct  collision  with  natural  philosophy.  The  great 
advance  of  comparative  anatomy,  physiolog}^  embry- 
ology, paleontology,  the  cell-theory,  and  classification, 
provided  scientists  with  such  ample  material  that  they 
attached  little  importance  to  speculative  metaphysics. 
It  was  otherwise  in  the  second  half  of  the  nineteenth 
century.     Soon   after   its    commencement   the    contro- 

70 


MIRACLES 

versy  about  the  immortality  of  the  soul  broke  out,  in 
which  Moleschott  (1852),  Biichner,  and  Carl  Vogt 
(1854)  contended  for  tlie  physiological  dependence  of  the 
soul  on  the  brain,  while  Rudolph  Wagner  endeavored  to 
maintain  the  prevailing  metaphysical  idea  of  its  super- 
natural character.  Then  Darwin  especially  initiated 
in  1859  that  vast  reform  in  biology  which  brought 
to  light  the  natural  origin  of  species  and  shattered 
the  miracle  of  creation.  When  the  application  of 
the  theory  of  descent  and  the  biogenetic  law  to  man 
was  made  by  anthropogeny  (1874),  and  his  evolution 
from  a  series  of  other  mammals  was  proved,  the  belief 
in  the  immortality  of  the  soul,  the  freedom  of  the 
will,  and  an  anthropomorphic  deity  lost  its  last  support. 
Nevertheless,  these  three  fundamental  dogmas  con- 
tinued to  find  favor  in  academic  philosophy,  which 
mostly  followed  the  paths  opened  out  by  Kant.  Most 
of  the  representatives  of  philosophy  at  the  universities 
are  narrow  metaphysicians  and  idealists,  who  think 
more  of  the  fiction  of  the  "intelligible  world "  than  of  the 
truth  of  the  world  of  sense.  They  ignore  the  vast  prog- 
ress made  by  modern  biology,  especially  in  the  science 
of  evolution;  and  they  endeavor  to  meet  the  difficulties 
which  it  creates  for  their  transcendental  idealism  by  a 
sort  of  verbal  gymnastic  and  sophistry.  Behind  all  these 
metaphysical  struggles  there  is  still  the  personal  element 
— the  desire  to  save  one's  immortality  from  the  wreck. 
In  this  it  comes  into  line  with  the  prevailing  theology, 
which  again  builds  on  Kant.  The  pitiful  condition  of 
modern  psychology  is  a  characteristic  result  of  this  state 
of  things.  While  the  empirical  physiology  and  pathol- 
ogy of  the  brain  have  made  the  greatest  discoveries,  the 
comparative  anatomy  and  histology  of  the  brain  have 
thrown  light  on  the  details  of  its  elaborate  structure,  and 
the  ontogeny  and  phylogeny  of  the  brain  have  proved  its 
natural  origin,  the  speculative  philosophy  of  the  schools 

71 


THE    WONDERS    OF    LIFE 

stands  aside  from  it  all,  and  in  its  introspective  analysis 
of  the  functions  of  the  brain  will  not  hear  a  word  about 
the  brain  itself.  It  would  explain  the  working  of  a  most 
complicated  machine  without  paying  any  attention  to  its 
structure.  It  is,  therefore,  not  surprising  to  find  that 
the  dualistic  theories  established  by  Kant  flourish  at  our 
universities  as  they  did  in  the  Middle  Ages. 

If  the  official  philosophers,  whose  formal  duty  it  is  to 
study  truth  and  natural  law.  still  cling  to  the  belief  in 
miracles  in  spite  of  all  the  advance  of  empirical  science, 
we  shall  not  be  surprised  to  find  this  in  the  case  of 
official  theology.  Nevertheless,  the  sense  of  truth  has 
prompted  many  unprejudiced  and  honorable  theologians 
to  look  critically  at  the  venerable  stmcture  of  dogma, 
and  open  their  minds  to  the  streaming  light  of  modem 
science.  In  the  first  third  of  the  nineteenth  century  a 
rationalistic  section  of  the  Protestant  Church  attempted 
to  rid  itself  of  the  fetters  of  dogma  and  reconcile  its  ideas 
with  pure  reason.  Its  chief  leader,  Schleiermacher,  of 
Berlin,  though  an  admirer  of  Plato  and  his  dualist 
metaphysics,  approached  very  close  to  modern  pan- 
theism. Subsequent  rationalistic  theologians,  especially 
those  of  the  Tubingen  school  (Baur,  Zeller,  etc.),  de- 
voted themselves  to  the  historical  study  of  the  gospels 
and  their  sources  and  development,  and  thus  more 
and  more  destroyed  the  base  of  Christian  supersti- 
tion. Finally,  the  radical  criticism  of  David  Friedrich 
Strauss  showed,  in  his  Life  of  Jesus  (1835),  the  mytho- 
logical character  of  the  whole  Christian  system.  In  his 
famous  work,  The  Old  and  Nciv  Faith  (1872),  this 
honorable  and  gifted  theologian  finally  abandoned  the 
belief  in  miracles,  and  turned  to  natural  knowledge  and 
the  monistic  philosophy  for  the  construction  of  a  rational 
view  of  life  on  the  basis  of  critical  experience.  This 
work  has  lately  been  continued  by  Albert  Kalthoff. 
Moreover,  many  modern  theologians  (such  as  Savage, 

72 


MIRACLES 

Nippold,  Pfleiderer,  and  other  liberal  Protestants)  have 
endeavored  in  various  ways  to  obtain  a  certain  recogni- 
tion for  the  claims  of  progressive  science,  and  reconcile 
them  with  theology,  while  discarding  the  belief  in  the 
miraculous.  However,  these  rationalistic  efforts,  based 
on  monistic  or  pantheistic  views,  are  still  isolated  and 
apparently  without  effect.  The  great  majority  of 
modern  theologians  adhere  to  the  traditional  teaching 
of  the  Church,  whose  columns  and  windows  are  still 
everywhere  adorned  with  miracles.  While  a  few  liberal 
Protestants  restrict  their  faith  to  the  three  fundamental 
dogmas,  most  of  them  still  believe  in  the  myths  and 
legends  which  fill  the  pages  of  the  gospels.  This  ortho- 
doxy is,  moreover,  encouraged  of  late  by  the  conserva- 
tive and  reactionary  attitude  taken  up  by  many  govern- 
ments on  political  grounds. 

Most  modern  governments  maintain  the  connection 
with  the  Church  in  the  idea  that  the  traditional  belief 
in  the  miraculous  is  the  best  security  for  their  own  con- 
tinuance. Throne  and  altar  must  protect  and  support 
each  other.  However,  this  conservative-Christian  policy 
meets  two  obstacles  in  an  increasing  measure.  On  the 
one  hand,  the  ecclesiastical  hierarchy  is  always  trying  to 
set  its  spiritual  power  above  the  seculai  and  make  the 
state  serve  its  own  purposes;  and,  on  the  other  hand, 
the  modern  right  of  popular  representation  affords  an 
opportunity  to  make  the  voice  of  reason  heard  and 
oppose  the  reactionary  conservatives  with  opportune 
reforms.  The  chief  rulers  and  the  ministers  of  public 
instruction,  who  have  a  great  influence  in  this  struggle, 
generally  favor  the  teaching  of  the  Church,  not  out  of 
conviction  of  its  truth,  but  because  they  think  knowl- 
edge brings  unrest,  and  because  docile  and  ignorant 
subjects  are  easier  to  rule  than  educated  and  independent 
citizens.  Hence  it  is  that  we  now  hear  so  much  on 
every   occasion,   in   speeches   from   the   throne   and   at 

73 


THE    WONDERS    OF    LIFE 

banquets,  at  the  opening  of  churches  and  the  unveiling 
of  monuments,  from  able  and  influential  speakers,  of  the 
value  of  faith.  They  would  give  the  palm  to  faith  in  its 
struggle  with  knowledge.  Thus  we  get  this  paradoxical 
situation  in  educated  countries  (such  as  Prussia),  that 
encouragement  is  given  at  once  to  modern  science  and 
technical  training  and  to  the  orthodox  Church,  which  is 
its  deadly  enemy.  As  a  rule,  it  is  not  stated  in  these 
florid  orations  to  how  many  and  what  kind  of  miracles 
this  precious  faith  must  extend.  Nevertheless,  we  may 
yet,  in  view  of  the  spread  of  intellectual  reaction  in 
Germany,  see  it  made  obligatory  for  at  least  all  priests, 
teachers,  and  other  servants  of  the  state  to  profess  a 
belief  in  the  three  fundamental  mysteries — the  triune 
God  of  the  catechism,  the  personal  immortality  of  the 
soul,  and  the  absolute  freedom  of  the  human  will — and 
even  in  many  of  the  other  miracles  which  are  found  in 
the  gospels,  sacred  legends,  and  religious  journals  of  our 
time. 

The  refined  belief  in  the  miraculous  embodied  in 
Kant's  practical  philosophy  assumed  many  different 
forms  among  his  followers,  the  Neo-Kantians,  approach- 
ing sometimes  more  and  sometimes  less  to  the  conven- 
tional beliefs.  Through  a  long  series  of  variations, 
which  still  continue  to  develop,  it  is  gradually  passing 
into  the  cruder  form  of  superstition  which  we  find 
popular  to-day  as  spiritism,  and  which  provides  the 
basis  for  what  is  called  occultism.  Kant  himself,  in 
spite  of  his  subtle  and  clear  critical  faculty,  had  a 
decided  leaning  to  mysticism  and  positive  dogmatism, 
which  showed  itself  especially  in  his  later  years.  He 
thought  a  good  deal  of  Swedenborg's  idea  of  the  spirit 
world  forming  a  universe  apart,  and  compared  this  to  his 
mundtis  intelligihilis.  Among  the  natural  philosophers 
of  the  first  half  of  the  nineteenth  century,  Schelling  (in 
his  later  writings),  Schubert  (in  his  History  of  the  Soul 

1Ar 


MIRACLES 

and  Observations  on  the  Dark  Side  of  Science),  and  Perty 
(in  his  mystic  anthropology)  especially  investigated  the 
mysterious  phenomena  of  mental  action,  and  sought  to 
connect  them  with  the  physiological  functions  of  the 
brain  on  the  one  hand  and  supernatural  spiritual  agen- 
cies on  the  other.  Modem  spook-seeking  has  no  more 
value  than  mediaeval  magic,  cabalism,  astrology,  necro- 
mancy, dream  -  interpretation,  and  invocation  of  the 
devil. 

We  must  put  at  the  same  stage  of  superstition  the 
spiritism  and  occultism  we  find  mentioned  so  much  in 
modern  literature.  There  are  always  thousands  of 
credulous  folk  in  educated  countries  who  are  taken  in  by 
the  performances  of  the  spiritists  and  their  media,  and 
are  ready  to  believe  the  unbelievable.  Spirit-rapping, 
table-turning,  spirit -writing,  the  materialization  and 
photographing  of  deceased  souls,  find  credit,  not  only 
among  the  uneducated  masses,  but  even  among  the  most 
cultured,  and  sometimes  among  imaginative  scientists. 
It  has  been  proved  without  avail  by  numbers  of  impartial 
observations  and  experiments  that  these  occultist  per- 
formances depend  partly  on  conscious  fraud  and  partly 
on  careless  self-deception.  Mttndns  vidt  decipi — "the 
world  wishes  to  be  taken  in" — as  the  old  saying  has  it. 
This  spiritistic  fraud  is  particularly  dangerous  when  it 
clothes  itself  with  the  mantle  of  science,  makes  use  of  the 
physiological  phenomena  of  hypnotism,  and  even  as- 
sumes a  monistic  character.  Thus,  for  instance,  one  of 
the  best  -  known  occultist  writers,  Karl  du  Prel,  has 
written,  not  only  a  Philosophy  of  Mysticism  and  Studies 
of  Scientific  Subjects,  but  also  (1888)  a  Monistic  Psychol- 
ogy, which  is  dualistic  from  beginning  to  end.  In  these 
popular  writings  lively  imagination  and  brilliant  pres- 
entation are  combined  with  a  most  flagrant  lack  of 
critical  sense  and  of  knowledge  of  the  elements  of  biology 
{cf.  chapter xvi.  of  the  Riddle).    It  seems  that  the  heredi- 

75 


THE    WONDERS    OF    LIFE 

tary  bias  towards  mysticism  and  superstition  is  not 
yet  eliminated  even  from  the  educated  mind  of  our  time. 
It  is  to  be  explained  phylogenetically  by  inheritance 
from  pre-historic  barbarians  and  savages,  in  whom  the 
earliest  religious  ideas  were  wholly  dominated  by 
animism  and  fetichism. 


IV 
THE  SCIENCE  OF  LIFE 

Object  of  biology — Relation  to  the  other  sciences — General  and 
special  biology — Natural  philosophy — Monism:  hylozoism, 
materialism,  dynamism — Naturalism — Nature  and  spirit — 
Physics  —  Metaphysics  —  Dualism  —  Freedom  and  natural 
law  —  God  in  biolog}'-  —  Realism  —  Idealism  —  Branches  of 
biology  —  Morphology  and  physiology  —  Anatomy  and  bi- 
ogeny — Ergology  and  perilogy. 

THE  broad  realm  of  science  has  been  vastly  extended 
in  the  course  of  the  nineteenth  century.  Many  new 
branches  have  established  themselves  independently; 
many  new  and  most  fruitful  methods  of  research  have 
been  discovered,  and  have  been  applied  with  the  great- 
est practical  success  in  furthering  the  advance  of  mod- 
em thought.  But  this  enormous  expansion  of  the  field 
of  knowledge  has  its  disadvantages.  The  extensive  di- 
vision of  labor  it  has  involved  has  led  to  the  growth 
of  a  narrow  specialism  in  many  small  sections;  and  in 
this  way  the  natural  connection  of  the  various  provinces 
of  knowledge,  and  their  relation  to  the  comprehensive 
whole,  have  been  partly  or  wholly  lost  sight  of.  The 
importation  of  new  terms  which  are  used  in  different 
senses  by  one-sided  workers  in  the  various  fields  of 
science  has  caused  a  good  deal  of  misunderstanding  and 
confusion.  The  vast  structure  of  science  tends  more 
and  more  to  become  a  tower  of  Babel,  in  the  lab3Tinthic 
passages  of  which  few  are  at  their  ease  and  few  any 
longer  understand  the  language  of  other  workers.     In 

77 


THE    WONDERS    OF    LIFE 

these  circumstances,  it  seems  advisable,  at  the  com- 
mencement of  our  philosophic  study  of  "the  wonders 
of  life,"  to  form  a  clear  idea  of  our  task.  We  must 
carefully  define  the  place  of  biology  among  the  sciences, 
and  the  relation  of  its  various  branches  to  each  other 
and  to  the  different  systems  of  philosophy. 

In  the  broadest  sense  in  which  we  can  take  it,  biolog}^ 
is  the  whole  study  of  organisms  or  living  beings.  Hence 
not  only  botany  (the  science  of  plants)  and  zoology 
(the  science  of  animals),  but  also  anthropology  (the 
science  of  man),  fall  within  its  domain.  We  then 
contiast  with  it  all  the  sciences  which  deal  with  in- 
organic or  lifeless  bodies,  which  we  may  collectively  call 
abiology  (or  anorganology) ;  to  this  belong  astronomy, 
geology,  mineralogy,  hydrology,  etc.  This  division  of 
the  two  great  branches  of  science  does  not  seem  difficult 
in  view  of  the  fact  that  the  idea  of  life  is  sharply  defined 
physiologically  by  its  metabolism  and  chemxically  by  its 
plasm;  but  when  we  comiC  to  study  the  question  of 
abicgenesis  (chapter  xv.)  we  shall  find  that  this  division  is 
not  absolute,  and  that  organic  life  has  been  evolved  from 
inorganic  nature.  ^loreover,  biology  and  abiology  are 
connected  branches  of  cosmology,  or  the  science  of  the 
world. 

While  the  idea  of  biology  is  now  usually  taken  in  this 
broad  sense  in  most  scientific  works  and  made  to  embrace 
the  whole  of  living  nature,  we  often  find  (especially  in 
Germany)  a  narrower  application  of  the  term.  Many 
authors  (mostly  physiologists)  understand  by  it  a 
section  of  physiology — namely,  the  science  of  the  rela- 
tions of  living  organisms  to  the  external  world,  their 
habitat,  customs,  enemies,  parasites,  etc.  I  proposed 
long  ago  to  call  this  special  part  of  biology  oecology  (the 
science  of  home-relations),  or  bionomy.  Twenty  A^ears 
later  others  suggested  the  name  of  ethology.  To  call 
this  special  study  any  longer  biology  in  the  narrower 

78 


THE    SCIENCE    OF    LIFE 

sense  is  very  undesirable,  because  it  is  the  only  name 
we  have  for  the  totality  of  the  organic  sciences. 

Like  every  other  science,  biology  has  a  general  and  a 
special  part.  General  biology  contains  general  informa- 
tion about  living  nature ;  this  is  the  subject  of  the  present 
study  of  the  wonders  of  life.  We  might  also  describe 
it  as  biological  philosophy,  since  the  aim  of  true  philos- 
ophy must  be  the  comprehensive  survey  and  rational 
interpretation  of  all  the  general  results  of  scientific 
research.  The  innumerable  discoveries  of  detailed  facts 
which  observation  and  experiment  give  us,  and  which 
are  combined  into  a  general  view  of  life  in  philosophy, 
form  the  subject  of  empirical  science.  As  the  latter,  on 
the  side  of  the  organic  world,  or  as  empirical  biology, 
forms  the  first  object  of  the  science  of  life,  and  seeks  to 
effect  in  the  system  of  nature  a  logical  arrangement  and 
summary  grouping  of  the  countless  special  forms  of  life, 
this  special  biology  is  often  wrongly  called  the  science 
of  classification. 

The  first  comprehensive  attempt  to  reduce  to  order 
and  unity  the  ample  biological  material  which  systematic 
research  had  accumulated  in  the  eighteenth  century  was 
made  by  what  we  call  "the  older  natural  philosophy" 
at  the  beginning  of  the  nineteenth  century.  Reinhold 
Treviranus  (of  Bremen)  had  made  a  suggestive  effort  to 
accomplish  this  difficult  task  on  monistic  principles  in 
his  Biology,  or  Philosophy  of  Living  Nature  (1802). 
Special  importance  attaches  to  the  year  1809,  in  which 
Jean  Lamarck  (of  Paris)  published  his  PhilosopJiie 
Zoologique,  and  Lorentz  Oken  (of  Jena)  his  Manual  of 
Natural  Philosophy.  I  have  fully  appreciated  the  service 
of  Lamarck,  the  founder  of  the  theory  of  descent,  in  my 
earlier  writings.  I  have  also  recognized  the  great  merit 
of  Lorentz  Oken,  who  not  only  aroused  a  very  wide 
interest  in  this  science  by  his  General  Natural  History, 
but  also  put  forward  some  general  observations  of  great 

79 


THE    WONDER  vS    OF    LIFE 

value.  His  "infamous "  theory  of  a  primitive  slime,  and 
the  development  of  infusoria  out  of  it,  is  merely  the 
fundamental  idea  of  the  theory  of  protoplasm  and  the 
cell  which  was  long  afterwards  fully  recognized.  These 
and  other  services  of  the  older  natural  philosophy  were 
partly  ignored  and  partly  overlooked,  because  they  went 
far  beyond  the  scientific  horizon  of  the  time,  and  their 
authors  to  an  extent  lost  themselves  in  airy  and  fantastic 
speculations.  The  more  scientists  confined  themselves 
in  the  following  half-century  to  empirical  work  and  the 
observation  and  description  of  separate  facts,  the  more 
it  became  the  fashion  to  look  down  on  all  "natural 
philosophy."  The  most  paradoxical  feature  of  the  situa- 
tion was  that  purely  speculative  philosophy  and  idealist 
metaphysics  had  a  great  inin  at  the  samie  time,  and  their 
castles  in  the  air,  utterly  destitute  of  biological  founda- 
tion, were  much  admired. 

The  magnificent  reform  of  biology  which  Darwin 
initiated  in  1859  by  his  epoch-making  Origin  of  Species 
gave  a  fresh  impulse  to  natural  philosophy.  As  this  work 
not  only  used  the  rich  collection  of  facts  already  made 
in  proof  of  the  theory  of  descent,  but  gave  it  a  new 
foundation  in  the  theory  of  selection  (Darwinism  prop- 
erly so  called),  everything  seemed  to  call  for  the 
embodiment  of  the  new  conception  of  nature  in  a 
monistic  system.  I  made  the  first  effort  to  do  this  in 
my  General  Morphology  (1866).  As  this  found  few 
supporters  among  my  colleagues,  I  undertook  in  my 
History  of  Creation  (1868)  to  make  the  chief  points  of  the 
system  accessible  to  the  general  reader.  The  remarkable 
success  of  this  book  (a  tenth  edition  of  it  appearing  in 
1902)  emboldened  me  at  the  end  of  the  nineteenth 
century  to  state  the  general  principles  of  my  monistic 
philosophy  in  my  Riddle  of  the  Universe.  About  the 
same  time  (1899)  there  appeared  the  work  of  the  Kiel 
botanist,  Johannes  Reinke,  The  World  as  Reality;  and 

80 


THE    SCIENCE    OF    LIFE 

two  years  afterwards  he  followed  it  up  with  a  supple- 
mentary volume,  Introduction  to  Theoretic  Biology.  As 
Reinke  treats  the  general  problenis  of  natural  philos- 
ophy from  a  purely  mystic  and  dualistic  point  of  view, 
his  ideas  are  diametrically  opposed  to  my  monistic  and 
naturalistic  principles. 

The  history  of  philosophy  describes  for  us  the  infinite 
variety  of  ideas  that  men  have  formulated  during  the 
last  three  thousand  years  on  the  nature  of  the  world  and 
its  phenomena.  Uberweg  has  given  us,  in  his  excellent 
History  of  Philosophy,  a  thorough  and  im^partial  account 
of  these  various  systems.  Fritz  Schultze  has  published 
a  clear  and  compendious  "tabulated  outline"  of  them 
in  thirty  tables  in  his  genealogical  tree  of  philosophy, 
and  at  the  same  time  shown  the  phylogeny  of  ideas. 
When  we  survey  this  enormxous  mass  of  philosophic 
systems  from  the  point  of  view  of  general  biology,  we 
find  that  we  can  divide  them  into  two  main  groups. 
The  first  and  smaller  group  contains  the  monistic  philos- 
ophy, which  traces  all  the  phenomena  of  existence  to 
one  single  common  principle.  The  second  and  larger 
group,  to  which  most  philosophic  systems  belong,  con- 
stitutes the  dualistic  philosophy,  according  to  which 
theie  are  two  totally  distinct  principles  in  the  universe. 
These  are  sometimes  expressed  as  God  and  the  world, 
sometimes  as  the  spiritual  world  and  material  world, 
sometimes  as  mind  and  matter,  and  so  on.  In  my 
opinion,  this  antithesis  of  monism  and  dualism  is  the 
most  important  in  the  whole  history  of  philosophy.  All 
other  svstems  are  onlv  variations  of  one  or  the  other  of 
these,  or  a  more  or  less  obscure  combination  of  the  two. 

The  form  of  monism  which  I  take  to  be  the  most  com- 
plete expression  of  the  general  truth,  and  which  I  have 
advocated  in  my  writings  for  thirty-eight  years,  is  now 
generally  called  hylozoism.  This  expresses  the  fact  that 
all  substance  has  two  fundamental  attributes ;  as  matter 
6  8i 


THE    WONDERS    OF    LIFE 

(hyle)  it  occupies  space,  and  as  force  or  energy  it  is 
endowed  with  sensation  {cf.  chapter  xix.).  Spinoza,  who 
gave  the  most  perfect  expression  to  this  idea  in  his 
"philosophy  of  identity,"  and  most  clearly  treated  the 
notion  of  substance  (as  the  all-embracing  essence  of  the 
world),  clothes  it  with  two  general  attributes — extension 
and  thought.  Extension  is  identical  with  real  space, 
and  thought  with  (unconscious)  sensation.  The  latter 
must  not  be  confused  with  conscious  human  thought; 
intelligence  is  not  found  in  substance,  but  is  a  special 
property  of  the  higher  animals  and  man.  Spinoza 
identifies  his  substance  with  nature  and  God,  and  his 
system  is  accordingly  called  pantheism;  but  it  must 
be  understood  that  he  rejects  the  anthropomorphic, 
personal  idea  of  deity. 

A  good  deal  of  the  infinite  confusion  that  characterizes 
the  conflicts  of  philosophers  over  their  systems  is  due 
to  the  obscurity  and  ambiguity  of  many  of  their  funda- 
mental ideas.  The  words  "substance"  and  "God," 
"soul"  and  "spirit,"  "sensation"  and  "matter,"  are 
used  in  the  most  different  and  changing  senses.  This 
is  especially  true  of  the  word  "materialism,"  which  is 
often  wrongly  taken  to  be  synonymous  with  monism. 
The  moral  bias  of  idealism  against  practical  materialism 
(or  pure  selfishness  and  sensualism)  is  forthwith  trans- 
ferred to  theoretical  materialism,  which  has  nothing  to 
do  with  it;  and  the  strictures  which  are  justly  urged 
against  the  one  are  most  unjustifiably  applied  to  the 
other.  Hence  it  is  important  to  distinguish  very  care- 
fully between  these  two  meanings  of  materialism. 

Theoretical  materialism  (or  hylonism),  as  a  realistic 
and  monistic  philosophy,  is  right  in  so  far  as  it  conceives 
matter  and  force  to  be  inseparably  connected,  and  denies 
the  existence  of  immaterial  forces.  But  it  is  wrong  when 
it  denies  all  sensation  to  matter,  and  regards  actual 
energy  as  a  function  of  dead  matter.     Thus,  in  ancient 

82 


THE    SCIENCE    OF    LIFE 

times  Democritus  and  Lucretius  traced  all  phenomena 
to  the  movements  of  dead  atoms,  as  did  also  Holbach 
and  Lamettrie  in  the  eighteenth  century.  This  view 
is  held  to-day  by  most  chemists  and  physicists.  They 
regard  gravitation  and  chemical  affinity  as  a  mere  me- 
chanical movement  of  atoms,  and  this,  in  turn,  as  the 
general  source  of  all  phenomena ;  but  they  will  not  allow 
that  these  movements  necessarily  presuppose  a  kind  of 
(unconscious)  sensation.  In  conversation  with  distin- 
guished physicists  and  chemists  I  have  often  found  that 
they  will  not  hear  a  word  about  a  "soul"  in  the  atom. 
In  my  opinion,  however,  this  must  necessarily  be  as- 
sumed to  explain  the  simplest  physical  and  chemical 
processes.  Naturally  I  am  not  thinking  of  anything  like 
the  elaborate  psychic  action  of  man  and  the  higher 
animals,  which  is  often  bound  up  with  consciousness; 
we  must  rather  descend  the  long  scale  of  the  develop- 
ment of  consciousness  until  we  reach  the  simplest  pro- 
tists,  the  monera  (chapter  ix.).  The  psychic  activity  of 
these  homogeneous  particles  of  plasm  (for  instance,  the 
chromacea)  rises  very  little  above  that  of  crystals;  as  in 
the  chemical  synthesis  in  the  moneron,  so  in  crystalliza- 
tion we  are  bound  to  assume  that  there  is  a  low  degree  of 
sensation  (not  of  consciousness),  in  order  to  explain  the 
orderly  arrangement  of  the  moving  molecules  in  a  defi- 
nite structure. 

The  prejudice  against  theoretical  materialism  (or  mate- 
rialistic monism)  which  still  prevails  so  much  is  partly 
due  to  its  rejection  of  the  three  central  dogmas  of 
dualist  metaphysics,  and  partly  to  a  confusion  of  it 
with  hedonism.  This  practical  materialism  in  its  ex- 
treme forms  (as  Aristippus  of  Cyrene  and  the  Cyrenaic 
school,  and  afterwards  Epicurus,  taught  it)  finds  the 
chief  end  of  life  in  pleasure — at  one  time  crude,  sensual 
pleasure,  and  at  others  spiritual  pleasure.  Up  to  a 
certain  point,  this  thirst  for  happiness  and  a  pleasant 

83 


THE    WONDERS    OF    LIFE 

and  enjoyable  life  is  innate  in  every  man  and  higher 
animal,  and  so  far  just;  it  only  began  to  be  censured  as 
sinful  when  Christianity  directed  the  thoughts  of  men 
to  eternal  life,  and  taught  them  that  their  life  on  earth 
was  only  a  preparation  for  the  future.  We  shall  see 
afterwards,  when  we  come  to  weigh  the  value  of  life 
(chapter  xvii.),  that  this  asceticism  is  unjustifiable  and 
unnatural.  But  as  every  legitimate  enjoyment  can 
become  wrong  by  excess,  and  every  virtue  be  turned 
into  vice,  so  a  narrow  hedonism  is  to  be  condemned, 
especially  when  it  allies  itself  with  egoism.  However, 
we  must  point  out  that  this  excessive  thirst  for  pleasure 
is  in  no  way  connected  with  materialism,  but  is  often 
found  among  idealists.  Many  convinced  supporters  of 
theoretical  materialism  (many  scientists  and  physicians, 
for  instance)  lead  very  simple,  blameless  lives,  and  are 
little  disposed  to  material  pleasures.  On  the  other  hand, 
many  priests,  theologians,  and  idealist  philosophers,  who 
preach  theoretical  idealism,  are  pronounced  hedonists  in 
practice.  In  olden  times  many  temples  served  at  one 
and  the  same  time  for  the  theoretic  worship  of  the  gods 
and  for  practical  excesses  in  the  way  of  wine  and  love; 
and  even  in  our  day  the  luxurious  and  often  vicious  lives 
of  the  higher  clergy  (at  Rome,  for  instance)  do  not  fall 
far  short  of  the  ancient  models.  This  paradoxical  situ- 
ation is  due  to  the  special  attractiveness  of  everything 
that  is  forbidden.  But  it  is  utterly  unjust  to  extend  the 
natural  feeling  against  excessive  and  egoistic  hedonism 
to  theoretical  materialism  and  to  monism.  Equally 
unjust  is  the  habit,  still  widely  spread,  of  depreciating 
matter,  as  such,  in  favor  of  spirit.  Impartial  biology 
has  taught  us  of  late  years  that  what  we  call  "spirit" 
is — as  Goethe  said  long  ago — inseparably  bound  up  with 
matter.  Experience  has  never  yet  discovered  any  spirit 
apart  from  matter. 

On  the  other  hand,  pure  dynamism,  now  often  called 

84 


THE    SCIENCE    OF    LIFE 

energism  (and  often  spiritualism),  is  just  as  one-sided 
as  pure  materialism.  Just  as  the  latter  takes  one  at- 
tribute of  substance,  matter,  as  the  one  chief  cause  of 
phenomena,  dynamism  takes  its  second  attribute,  force 
(dynantis).  Leibnitz  most  consistently  developed  this 
system  among  the  older  German  philosophers;  and 
Fechner  and  Zollner  have  recently  adopted  it  in  part. 
The  latest  development  of  it  is  found  in  Wilhelm 
Ostwald's  Natural  PhilusopJiy  (1902).  This  work  isT) 
purely  monistic,  and  very  ingeniously  endeavors  to 
show  that  the  same  forces  are  at  work  in  the  whole  of 
nature,  organic  and  inorganic,  and  that  these  may  all  be 
comprised  under  the  general  head  of  energy.  It  is 
especially  satisfactory  that  Ostwald  has  traced  the 
highest  functions  of  the  human  mind  (consciousness, 
thought,  feeling,  and  will),  as  well  as  the  simplest 
physical  and  chemical  processes  (heat,  electricity,  chem- 
ical affinity,  etc  ),  to  special  forms  of  energy,  or  natural 
force.  However,  he  is  wrong  when  he  supposes  that  his 
energism  is  an  entirely  new  system^  The  chief  points  of 
it  are  found  in  Leibnitz;  and  other  Leipzig  scientists, 
especially  Fechner  and  Zollner,  had  come  very  close  to 
similar  spiritualistic  views — the  latter  going  into  out- 
right spiritism.  Ostwald's  chief  mistake  is  to  take  the 
terms  "energy"  and  "substance"  to  be  synonymous. 
Certainly  his  universal,  all -creating  energy  is,  in  the 
main,  the  same  as  the  substance  of  Spinoza,  which  we 
have  also  adopted  in  our  "law  of  substance."  But 
Ostwald  would  deprive  substance  of  the  attribute  of 
matter  altogether,  and  boasts  of  his  Rcjiitation  of 
Materialism  (1895).  He  would  leave  it  only  the  one 
attribute,  energy,  and  reduce  all  matter  to  immaterial 
jjoints  of  force.  Nevertheless,  as  chemist  and  physicist, 
he  never  gets  rid  of  space-filling  substance  —  which  is 
all  we  mean  by  "matter" —  and  has  to  treat  it  and  its 
parts,  the  physical  molecules  and  chemical  atoms  (even 

85 


THE    WONDERS    OF    LIFE 

if  only  conceived  as  symbols),  daily  as  "vehicles  of 
energy."  Ostwald  would  reject  even  these  in  his  pur- 
suit of  the  illusion  of  a  "science  without  hypotheses." 
As  a  fact,  he  is  forced  every  day,  like  every  other  exact 
scientist,  to  assume  and  apply  in  practice  the  indis- 
pensable idea  of  matter,  and  its  separate  particles,  the 
molecules  and  atoms.     Knowledge  is  impossible  with- 

...out  hypotheses. 

'  Monism  is  best  expressed  as  hylozoism,  in  so  far  as  this 
removes  the  antithesis  of  materialism  and  spiritualism 
(or  mechanicism  and  dynamism),  and  unites  them  in  a 
natural  and  harmonious  system.  Our  monistic  system 
has  been  charged  with  leading  to  pure  naturalism;  one 
of  its  miost  vehement  critics,  Frederick  Paulsen,  attaches 
so  much  importance  to  this  stricture  that  he  thinks  it  as 
dangerous  as  dogmatic  clericalism.  We  may,  therefore, 
usefully  consider  the  idea  of  naturalism,  and  point  out  in 
what  sense  we  accept  it  and  identify  it  with  monism. 
The  key  to  the  position  is  in  our  monistic  anthropogeny, 
our  unprejudiced  conviction,  supported  by  every  branch 
of  anthropological  research,  of  "mian's  place  in  nature," 
as  we  have  established  it  in  the  first  section  of  the  Riddle 
(chapters  ii.-v.).  Man  is  a  purely  natural  being,  a 
placental  mammal  of  the  order  of  primates.  He  was 
phylogenetically  evolved  in  the  course  of  the  Tertiary 
Peiiod  from  a  series  of  the  lower  primates  (directly  from 
the  anthropoid  apes,  but  earlier  from  the  cynocephali 
and  lemures).  Savage  man,  as  we  have  him  to-day  in 
the  Veddah  or  Australian  negro,  is  physiologically  nearer 
to  the  apes  than  to  highly  civilized  men. 

Anthropology  (in  the  widest  sense)  is  only  a  particular 
branch  of  zoology,  to  which  we  must  assign  a  special 
position  on  account  of  its  extreme  importance.  Hence 
all  the  sciences  which  relate  to  man  and  his  psychic 
activity — especially  what  are  called  the  moral  sciences — 
must  be  regarded  from  our  monistic  point  of  view  as 

86 


THE    SCIENCE    OF    LIFE 

special  branches  of  zoology  and  as  natural  sciences. 
Human  psychology  is  inseparably  connected  with  com- 
parative animal  psychology,  and  this  again  with  that  of 
the  plants  and  protists.  Philology  studies  in  human 
speech  a  complicated  natural  phenomenon,  which  de- 
pends on  the  combined  action  of  the  brain-cells  of  the 
phronema,  the  muscles  of  the  tongue,  and  the  vocal 
cords  of  the  larynx,  as  much  as  the  cry  of  mammals  and 
the  song  of  birds  do.  The  history  of  mankind  (which 
we,  in  our  curious  anthropocentric  mood,  call  the  history 
of  the  world),  and  its  highest  branch,  the  history  of 
civilization,  is  connected  by  modern  pre-historic  science 
directly  with  the  stem-history  of  the  primates  and  the 
other  mammals,  and  indirectly  with  the  phylogeny 
of  the  lower  vertebrates.  Hence,  when  we  consider 
the  subject  without  prejudice,  we  do  not  find  a  single 
branch  of  human  science  that  passes  the  limits  of 
natural  science  (in  the  broadest  sense),  any  more  than 
we  find  nature  herself  to  be  supernatural. 

Just  as  monism,  or  naturalism,  embraces  the  totality 
of  science,  so  on  our  principles  the  idea  of  nature  com- 
prises the  whole  scientifically  knowable  world.  In  the 
strict  monistic  sense  of  Spinoza  the  ideas  of  God  and 
Nature  are  synonymous  for  us.  Whether  there  is  a 
realm  of  the  supernatural  and  spiritual  beyond  nature 
we  do  not  know.  All  that  is  said  of  it  in  religious  myths 
and  legends,  or  metaphysical  speculations  and  dogmas, 
is  mere  poetry  and  an  outcome  of  imagination.  The^ 
imagination  of  civilized  man  is  ever  seeking  to  produce 
unified  images  in  art  and  science,  and  when  it  meets 
with  gaps  in  these  in  the  association  of  ideas  it  en- 
deavors to  fill  them  with  its  own  creations.  These 
creations  of  the  phronema  with  which  we  fill  the  gaps  in 
our  knowledge  are  called  hypotheses  when  they  are  in 
harmony  with  the  empirically  established  facts,  and 
myths  when  they  contradict  the  facts:  this  is  the  casQ 

87 


J 


THE    WONDERS    OF    LIFE 

with  religious  myths,  miracles,  etc.  Even  when  people 
contrast  mind  with  nature,  this  is  only  a  result,  as  a  rule, 
of  similar  superstitions  (animism,  spiritism,  etc.).  But 
when  we  speak  of  man's  mind  as  a  higher  psychic 
function,  we  mean  a  special  physiological  function  of  the 
brain,  or  that  particular  part  of  the  cortex  of  the  brain 
which  we  call  the  phronema,  or  organ  of  thought.  This 
higher  psychic  function  is  a  natural  phenomenon,  sub- 
ject, like  all  other  natural  phenomena,  to  the  law  of 
substance.  The  old  Latin  word  natura  (from  nasci,  to  be 
born)  stands,  like  the  corresponding  Greek  term  physis 
(from  phyo — to  grow) ,  for  the  essence  of  the  world  as  an 
eternal  "being  and  becoming"  —  a  profound  thought! 
Hence  physics,  the  science  of  the  physis,  is,  in  the 
broadest  sense  of  the  word,  "natural  science." 

The  extensive  division  of  labor  which  has  taken  place 
in  science,  on  account  of  the  enormous  growth  of  our 
knowledge  in  the  nineteenth  century  and  the  rise  of 
many  new  disciplines,  has  very  much  altered  their 
relations  to  each  other  and  to  the  whole,  and  has  even 
given  a  fresh  meaning  and  connotation  to  the  term. 
Hence  by  physics,  as  it  is  now  taught  at  the  universities, 
is  usually  understood  only  that  part  of  inorganic  science 
which  deals  with  the  molecular  relations  of  substance 
and  the  mechanism  of  mass  and  ether,  without  regard 
to  the  qualitative  differences  of  the  elements,  which  are 
expressed  in  the  atomic  weight  of  their  smallest  particles, 
the  atoms.  The  study  of  the  atoms  and  their  affinities 
and  combinations  belongs  to  chemistry.  As  this  province 
is  very  extensive  and  has  its  special  methods  of  research, 
it  is  usually  put  side  by  side  with  physics  as  of  equal 
importance;  in  reality,  however,  it  is  only  a  branch  of 
physics — chemistry  is  the  physics  of  the  atoms.  Hence, 
when  we  speak  of  a  physico  -  chemical  inquiry  or  phe- 
nomenon, we  might  justly  describe  it  briefly  as  physical 
(in  the  wider  sense).     Physiology,  again,  a  particularly 

88 


THE    SCIENCE    OF    LIFE 

important  branch  of  it,  is  in  this  sense  the  physics  of 
Hving  things,  or  the  physico-chemical  study  of  the  Uving 
body. 

Since  Aristotle  dealt  with  the  eternal  phenomena  of 
nature  in  the  first  part  of  his  works,  and  called  this 
physics,  and  with  their  inner  nature  in  the  second  part, 
to  which  he  gave  the  name  of  metaphysics,  the  two  terms 
have  undergone  many  and  considerable  modifications.  If 
we  restrict  the  term  "physics"  to  the  empirical  study  of 
phenomena  (by  observation  and  experiment),  we  may 
give  the  name  of  metaphysics  to  every  hypothesis  and 
theory  that  is  introduced  to  fill  up  the  gaps  in  it.  In 
this  sense  the  indispensable  theories  of  physics  (such  as 
the  assumption  that  matter  is  made  up  of  molecules  and 
atoms  and  electrons)  may  be  described  as  metaphysical ; 
such  also  is  our  assumption  that  all  substance  is  endowed 
with  sensation  as  well  as  extension  (matter).  This 
monistic  metaphysics,  which  recognizes  the  absolute 
dominion  of  the  law  of  substance  in  all  phenomena,  but 
confines  itself  to  the  study  of  nature  and  abandons 
inquiry  into  the  supernatural,  is,  with  all  its  theories 
and  hypotheses,  an  indispensable  part  of  any  rational 
philosophy  of  life.  To  claim,  as  Ostwald  does,  that 
science  must  be  free  from  hypotheses  is  to  deprive  it  of  its 
foundations.  But  it  is  very  different  with  the  current 
dualistic  metaphysics,  which  holds  that  there  are  two 
distinct  worlds,  and  which  we  find  in  a  hundred  forms 
as  philosophic  dualism. 

If  we  understand  by  metaphysics  the  science  of  the 
ultimate  ground  of  things,  springing  from  the  rational 
demand  for  causes,  it  can  only  be  regarded,  from  the 
physiological  point  of  view,  as  a  higher  and  late-devel- 
oped function  of  the  phronema.  It  could  only  arise  with 
the  complete  development  of  the  brain  in  civilized  man. 
It  is  completely  lacking  among  savages,  whose  organ  of 
thought  rises  very  little  above  that  of  the  most  intelligent 

89 


THE    WONDERS    OF    LIFE 

animals.  The  laws  of  the  psychic  life  of  the  savage  have 
been  closely  studied  by  modem  ethnology.  It  teaches 
us  tha-t  the  higher  reason  is  not  found  in  savages,  and 
that  their  power  of  abstract  thought  and  of  forming 
concepts  is  at  a  very  low  level.  Thus,  for  instance,  the 
Veddahs,  who  live  in  the  forests  of  Ceylon,  have  not  the 
general  idea  of  trees,  though  they  know  and  give  names 
to  individual  trees.  Many  savages  cannot  count  up  to 
five;  they  never  reflect  on  the  ground  of  their  existence 
or  think  of  the  past  or  future.  Hence  it  is  a  great  error 
for  Schopenhauer  and  other  philosophers  to  define  man 
as  a  "metaphysical  animal,"  and  to  seek  a  profound 
distinction  between  man  and  the  animal  in  the  need  for 
a  metaphysic.  This  craving  has  only  been  awakened 
and  developed  by  the  progress  of  civilization.  But  even 
in  civilized  communities  it  (like  consciousness)  is  not 
found  in  early  youth,  and  only  gradually  emerges.  The 
child  has  to  learn  to  speak  and  think.  In  harmony  with 
our  biogenetic  law,  the  child  reproduces  in  the  various 
stages  of  its  mental  development  the  whole  of  the 
gradations  which  lead  from  the  savage  to  the  barbarian, 
and  from  the  barbarian  to  the  half -civilized,  and  on  to 
the  fully  educated  man.  If  this  historical  development 
of  the  higher  human  faculties  had  always  been  properly 
appreciated,  and  psychology  had  been  faithful  to  the 
comparative  and  genetic  methods,  many  of  the  errors  of 
the  current  metaphysical  systems  would  have  been 
avoided.  Kant  would  not  then  have  produced  his  theory 
of  a  priori  knowledge,  but  would  have  seen  that  all  that 
now  seems  to  be  a  priori  in  civilized  man  was  originally 
acquired  by  a  posteriori  experiences  in  the  long  evolution 
of  civilization  and  science.  Here  we  have  the  root  of  the 
errors  which  are  distinctive  of  dualism  and  the  prevail- 
ing metaphysical  transcendentalism. 

Like  all  science,  biology  is  realistic — that  is  to  say, 
it  regards  its  object,  the  organisms,  as  really  existing 

90 


THE    SCIENCE    OF    LIFE 

things,  the  features  of  which  are  to  an  extent  knowable 
through  our  senses  {sciisoriuni)  and  organ  of  thought 
{phronema).  At  the  same  time,  we  know  that  these 
cognitive  organs,  and  the  knowledge  they  bring  us,  are 
imperfect,  and  that  there  may  be  other  features  of 
organisms  that  he  beyond  our  means  of  perception 
altogether.  But  it  by  no  means  follows  from  this  that, 
as  our  idealist  opponents  say,  the  organisms  (and  all 
other  things)  exist  only  in  our  mind  (in  the  images  in 
our  cortex).  Our  pure  monism  (or  hylozoism)  agrees 
with  realism  in  recognizing  the  unity  of  being  of  each 
organism,  and  denying  that  there  is  any  essential  dis- 
tinction between  its  knowable  phenomenon  and  its 
internal  hidden  essence  (or  noumenon),  whether  the 
latter  be  called,  with  Plato,  the  eternal  "idea,"  or,  with 
Kant,  the  "thing  in  itself."  Realism  is  not  identical 
with  materialism,  and  may  even  be  definitely  connected 
with  the  very  opposite,  dynamism  or  energism. 

As  realism  generally  coincides  with  monism,  so  ideal- 
ism is  usually  identical  with  dualism.  The  two  most 
influential  representatives  of  dualism,  Plato  and  Kant, 
said  that  there  were  two  totally  distinct  worlds.  Nat- 
ure, or  the  empirical  world,  is  alone  accessible  to  our 
experience,  while  the  spiritual  or  transcendental  world 
is  not.  The  existence  of  the  latter  is  known  to  us 
only  by  the  emotions  or  by  practical  reason ;  but  we 
can  have  no  idea  of  its  nature.  The  chief  error  of  this 
theoretical  idealism  is  the  assumption  that  the  soul  is  a 
peculiar,  immaterial  being,  immortal  and  endowed  with 
a  priori  knowledge.  The  physiology  and  ontogeny  of 
the  brain  (together  with  the  comparative  anatomy  and 
histology  of  the  phronema)  prove  that  the  soul  of  man 
is,  like  that  of  all  other  vertebrates,  a  function  of  the 
brain,  and  inseparably  bound  up  with  this  organ.  Hence 
this  idealist  theory  of  knowledge  is  just  as  inconsist- 
ent  with   realistic   biology   as   is  the  psycho  -  physical 

9? 


THE    WONDERS    OF    LIFE 

parallelism  of  Wundt  or  the  psycho-monism  of  more 
recent  physiologists,  which  in  the  end  issues  in  a  com- 
plete dualism  of  body  and  mind.  It  is  otherwise 
with  practical  idealism.  When  this  presents  the  sym- 
bols or  ideals  of  a  personal  God,  an  immortal  soul, 
and  the  free-will  as  ethical  stimuli,  and  uses  them  for 
their  pedagogical  worth  in  the  education  of  the  young, 
it  may  have  a  good  influence  for  a  time,  which  is  in- 
dependent of  their  theoretical  untenability. 

The  many  branches  of  biology  which  have  been 
developed  independently  in  the  course  of  the  nineteenth 
century  ought  to  remain  in  touch  with  one  another,  and 
co-operate  with  a  clear  apprehension  of  their  task,  if 
they  are  to  attain  their  high  purpose  of  framing  a 
unified  science  embracing  the  whole  field  of  organic 
life.  Unfortunately,  this  common  aim  is  often  lost 
sight  of  in  the  specialization  of  study ;  the  philosophical 
task  is  neglected  in  favor  of  the  empirical.  The  con- 
fusion that  has  ensued  makes  it  desirable  to  determine 
the  mutual  positions  of  the  various  biological  disciplines. 
I  went  into  this  somewhat  fully  in  my  academic  speech 
on  the  development  and  aim  of  zoology  in  1869.  But 
as  this  essay  is  little  known,  I  will  briefly  resume  the 
chief  points  of  it. 

In  correspondence  with  the  long-established  distinc- 
tion between  the  plant  and  the  animal,  the  two  chief 
branches  of  biology,  zoology  and  botany,  have  developed 
side  by  side,  and  are  represented  by  two  different  chairs 
in  the  universities.  Independently  of  these,  there  arose 
at  the  very  beginning  of  scientific  activity  that  field  of 
inquiry  which  deals  with  human  life  in  all  its  aspects — 
the  anthropological  disciplines  and  the  so-called  "mental 
sciences"  (history,  philology,  psychology,  etc.).  Since 
the  theory  of  descent  has  proved  man's  origin  from 
vertebrate  ancestors,  and  thus  anthropology  has  been 
recognized  as  a  part  of  zoology,  we  have  begun  to  un- 

92 


THE    SCIENCE    OF    LIFE 

derstand  the  inner  historic  connection  between  these 
various  branches  of  anthropology,  and  to  combine  them 
in  a  comprehensive  science  of  man.  The  immense  ex- 
tent and  the  great  importance  of  this  science  have 
justified  the  creation  of  late  years  of  special  chairs  of 
anthropology.  It  seems  desirable  to  do  the  same  for  the 
science  of  the  protists,  or  unicellular  organisms.  The 
cell  theory,  or  cytology,  as  an  elementary  part  of  anat- 
omy, has  to  be  dealt  with  in  both  botany  and  zoology; 
but  the  lowest  unicellular  representatives  of  both 
kingdoms,  the  primitive  plants  (protophyta)  and  the 
primitive  animals  (protozoa),  are  so  intimately  con- 
nected, and  throw  so  great  a  light,  as  independent  rudi- 
mentary organisms,  on  the  tissue  cells  in  the  histon,  or 
multicellular  organism,  that  we  must  regard  as  a  sign 
of  progress  the  recent  proposal  of  Schaudinn  to  found 
a  special  institute  and  journal  for  the  science  of  protists. 
One  very  important  section  of  it  is  bacteriology. 

The  practical  division  of  biology,  according  to  the 
extent  of  the  organic  kingdom,  leads  us  to  mark  out  four 
chief  provinces  of  research:  protistology  (the  science  of 
the  unicellulars) ,  botany  (the  science  of  plants),  zoology 
(the  science  of  animals),  and  anthropology  (the  science 
of  man).  In  each  of  these  four  fields  we  may  then 
distinguish  morphology  (the  science  of  forms)  and 
physiology  (the  science  of  functions)  as  the  two  chief 
divisions  of  scientific  work.  The  special  methods  and 
means  of  observation  differ  entirely  in  the  two  sections. 
In  morphology  the  work  of  description  and  comparison 
is  the  most  important  as  regards  both  outer  form  and 
inner  structure.  In  physiology  the  exact  methods  of 
physics  and  chemistry  are  especially  demanded — the 
observation  of  vital  activities  and  the  attempt  to  dis- 
cover the  physical  laws  that  govern  them.  As  a  correct 
knowledge  of  human  anatomy  and  physiology  is  indis- 
pensable for  scientific  medicine,  and  the  work  requires  a 

93 


THE    WONDERS    OF    LIFE 

particularly  large  apparatus,  these  two  sciences  have 
long  been  studied  separately,  and  have  been  handed  over 
to  the  medical  faculty  in  the  division  of  the  academic 
curriculum. 

The  broad  field  of  morphology  may  be  divided  into 
anatomy  and  biogeny;  the  one  deals  with  the  fully 
developed,  and  the  other  with  the  developing,  organism. 
Anatomy,  the  study  of  the  foniied  organism,  studies  both 
the  external  form  and  the  inner  structure.  We  may 
distinguish  as  its  two  branches  the  science  of  structures 
(tectology)  and  the  science  of  fundamental  forms  (pro- 
morphology).  Tectology  investigates  the  features  of  the 
structure  in  the  organic  individual,  and  the  composition 
of  the  body  out  of  various  parts  (cells,  tissues,  and 
organs) .  Promorphology  describes  the  real  form  of  these 
individual  parts  and  of  the  whole  body,  and  endeavors 
to  reduce  them  mathematically  to  certain  fundamental 
forms  (chapter  viii.).  Biogeny,  or  the  science  of  the 
evolution  of  organisms,  is  also  divided  into  two  parts — 
the  science  of  the  individual  (ontogeny)  and  of  the  stem 
or  species  (phylogeny) ;  each  follows  its  own  peculiar 
methods  and  aims,  but  they  are  most  intimately  con- 
nected by  the  biogenetic  law.  Ontogeny  deals  with  the 
development  of  the  individual  organism  from  the  begin- 
ning of  its  existence  to  death;  as  embryology  it  ob- 
serves the  growth  of  the  individual  within  the  foetal 
membranes;  and  as  metamorphology  (or  the  science  of 
metamorphoses)  it  follows  the  subsequent  changes  in  post- 
foetal  life  (chapter  xvi.).  The  task  of  phylogeny  is  to 
trace  the  evolution  of  the  organic  stem  or  species — that  is 
to  say,  of  the  chief  divisions  in  the  animal  and  plant 
worlds,  which  we  describe  as  classes,  orders,  etc. ;  in  other 
words,  it  traces  the  genealogy  of  species.  It  relies  on  the 
facts  of  paleontology,  and  fills  up  the  gaps  in  this  by 
comparative  anatomy  and  ontogeny. 

The  science  of  the  vital  phenomena,  which  we  call 

94 


THE    SCIENCE    OF    LIFE 

physiology,  is  for  the  most  part  the  physiology  of  work, 
or  ergology;  it  investigates  the  functions  of  the  living 
organism,  and  has  to  reduce  them  as  closely  as  possible 
to  physical  and  chemical  laws.  Vegetable  ergology  deals 
with  what  are  called  the  vegetative  functions,  nutrition 
and  reproduction ;  animal  ergology  studies  the  animal 
activities  of  movement  and  sensation.  Psychology  is 
directly  connected  with  the  latter.  But  the  study  of  the 
relations  of  the  organism  to  its  environment,  organic  and 
inorganic,  also  belongs  to  physiology  in  the  wider  sense; 
we  call  this  part  of  it  perilogy,  or  the  physiology  of 
relations.  To  this  belong  chorology,  or  the  science  of 
distribution  (also  called  biological  geography,  as  it 
deals  with  geographical  and  topographical  distribution), 
and  oecology  or  bionomy  (also  recently  called  ethol- 
ogy), the  science  of  the  domestic  side  of  organic  life,  of 
the  life-needs  of  organisms  and  their  relations  to  other 
organisms  with  which  they  live  (biocenosis,  symbiosis, 
parasitism) . 


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V 

DEATH 

Life  and  death — Individual  death — ImmortaHty  of  the  uni- 
cellulars — Death  of  the  protists  and  tissue-organisms — 
Causes  of  physiological  death — Using  up  of  the  plasma — 
Regeneration — Biotonus — Perigenesis  of  the  plastidulcs: 
memory  of  the  biogens — Regeneration  of  protists  and 
tissue-organisms — Senile  debility — Disease — Necrobiosis — 
The  lot  of  death — Providence — Chance  and  fate — Eternal 
life — Optimism  and  pessimism — Suicide  and  self-redemp- 
tion— Redemption  from  evil — Medicine  and  philosophy — 
Maintenance  of  life — Spartan  selection. 

NOTHING  is  constant  but  change!  All  existence  is  a 
perpetual  flux  of  "being  and  becoming"!  That  is 
the  broad  lesson  of  the  evolution  of  the  world,  taken  as  a 
whole  or  in  its  various  parts.  Substance  alone  is  eternal 
and  unchangeable,  whether  we  call  this  all-embracing 
world-being  Nature,  or  Cosmos,  or  God,  or  World-spirit. 
The  law  of  substance  teaches  us  that  it  reveals  itself  to 
us  in  an  infinite  variety  of  forms,  but  that  its  essential 
attributes,  matter  and  energy,  are  constant.  All  indi- 
vidual forms  of  substance  are  doomed  to  destruction. 
That  will  be  the  fate  of  the  sun  and  its  encircling  planets, 
and  of  the  organisms  that  now  people  the  earth — 
the  fate  of  the  bacterium  and  of  man.  Just  as  the 
existence  of  every  organic  individual  had  a  beginning,  it 
will  also  undeniably  have  an  end.  Life  and  death  are 
irrevocably  united.  However,  philosophers  and  biolo- 
gists hold  very  different  views  as  to  the  real  causes  of 
this  destiny.  Most  of  their  opinions  are  at  once  out  of 
court,  because  they  have  not  a  clear  idea  of  the  nature  of 
7  97 


THE    WONDERS    OF    LIFE 

life,  and  so  can  have  no  adequate  idea  of  its  termination 
— death. 

The  inquiry  into  the  nature  of  organic  life  which  we 
instituted  in  the  second  chapter  has  shown  us  that  it  is, 
in  the  ultimate  analysis,  a  chemical  process.  The 
"  miracle  of  life  "  is  in  essence  nothing  but  the  metab- 
olism of  the  living  matter,  or  of  the  plasm.  Recent 
physiologists,  especially  Max  Verworn  and  Max  Kasso- 
witz,  have  pointed  out,  in  opposition  to  modern  vitalism, 
that  "  life  consists  in  a  continuous  alternation  between 
the  upbuild  and  the  decay  of  the  highly  complicated 
chemical  unities  of  the  protoplasm.  And  if  this  concep- 
tion is  admitted,  we  may  rightly  say  that  we  know  what 
we  mean  by  death.  If  death  is  the  cessation  of  life,  we 
must  mean  by  that  the  cessation  of  the  alternation 
between  the  upbuild  and  the  dissolution  of  the  mole- 
cules of  protoplasm;  and  as  each  of  the  molecules  of  pro- 
toplasm must  break  up  again  shortly  after  its  formation, 
we  have  in  death  to  deal  only  with  the  definite  cessation 
of  reconstruction  in  the  destroyed  plasma-molecules. 
Hence  a  living  thing  is  not  finally  dead — that  is  to  say, 
absolutely  incompetent  to  discharge  any  further  vital 
function — until  the  whole  of  its  plasma-molecules  are 
destroyed."  In  the  exhaustive  justification  with  which 
Kassowitz  follows  up  this  definition  in  the  fifteenth 
chapter  of  his  General  Biology,  the  natural  causes  of 
physiological  death  are  fully  described. 

Among  the  numerous  and  contradictory  views  of 
recent  biologists  on  the  nature  of  death  we  find  many 
errors  and  misunderstandings,  due  to  a  lack  of  clear 
distinction  between  the  duration  of  the  living  matter  in 
general  and  that  of  the  individual  life-form.  This  is 
particularly  noticeable  in  the  contradictory  views  which 
have  been  elicited  by  August  Weismann's  theory  (1882) 
of  the  immortality  of  the  unicellulars.  I  have  shown  in 
the  eleventh  chapter  of  the  Riddle  that  it  is  untenable. 

98 


DEATH 

But  as  the  distinguished  zoologist  has  again  taken  up 
his  theory  with  energy  in  his  instructive  Lectures  on  the 
Theory  of  the  Descent  (1902),  and  has  added  to  it  er- 
roneous observations  on  the  nature  of  death,  I  am 
obliged  to  return  to  the  point.  Precisely  because  this 
interesting  work  gives  most  valuable  support  to  the 
theory  of  evolution,  and  maintains  Darwin's  theory  of 
selection  and  its  consequences  with  great  effect,  I  feel  it 
is  necessary  to  point  out  considerable  weaknesses  and 
dangerous  errors  in  it.  The  chief  of  these  is  the  im- 
portant theory  of  the  germ-plasm  and  the  consequent 
opposition  to  the  inheritance  of  acquired  characteristics. 
Weismann  deduces  from  this  a  radical  distinction  be- 
tween the  unicellular  and  the  multicellular  organisms. 
The  latter  alone  are  mortal,  the  former  immortal;  "be- 
tween the  unicellular  and  the  multicellular  lies  the  intro- 
duction of  physiological — that  is  to  say,  normal — death." 
We  must  say,  in  opposition  to  this,  that  the  physiological 
individuals  (bionta)  among  the  protista  are  just  as 
limited  in  their  duration  as  among  the  histona.  But  if 
the  chief  stress  in  the  question  is  laid,  not  on  the  in- 
dividuality of  the  living  matter,  but  on  the  continuity 
of  the  metabolic  life-movement  through  a  series  of 
generations,  it  is  just  as  correct  to  affirm  a  partial 
immortality  of  the  plasm  for  the  multicellulars  as  for 
the  unicellulars. 

The  immortality  of  the  unicellulars,  on  which  Weis- 
mann has  laid  so  much  stress,  can  only  be  sustained 
for  a  small  part  of  the  protists  even  in  his  own  sense — 
namely,  for  those  which  simply  propagate  by  cleavage, 
the  chromacea  and  bacteria  among  the  monera  (chapter 
ix.) ,  the  diatomes  and  paulotomes  among  the  protophy  ta, 
and  a  part  of  the  infusoria  and  rhizopods  among  the 
protozoa.  Strictly  speaking,  the  individual  life  is 
destroyed  when  a  cell  splits  into  two  daughter-cells. 
One  might  reply  with  Weismann  that  in  this  case  the 

99 


THE    WONDERS    OF    LIFE 

dividing  unicellular  organism  lives  on  as  a  whole  in  its 
offspring,  and  that  we  have  no  corpse,  no  dead  remains 
of  the  living  matter,  left  behind.  But  that  is  not  true 
of  the  majority  of  the  protozoa.  In  the  highly  devel- 
oped ciliata  the  chief  nucleus  is  lost,  and  there  must  be 
from  time  to  time  a  conjugation  of  two  cells  and  a  mutual 
fertilization  of  their  secondary  nuclei,  before  there  can 
be  any  further  multiplication  by  simple  cleavage.  How- 
ever, in  most  of  the  sporozoa  and  rhizopoda,  which 
generally  propagate  by  spore  formation,  only  one  por- 
tion of  the  unicellular  organism  is  used  for  this ;  the  other 
portion  dies,  and  forms  a  "corpse."  In  the  large 
rhizopods  (thalamophora  and  radiolaria)  the  spore- 
forming  inner  part,  which  lives  on  in  the  offspring,  is 
smaller  than  the  decaying  outer  portion,  which  becomes 
the  corpse. 

Weismann's  view  of  the  secondary  "introduction  of 
physiological  death  in  the  multicellulars"  is  just  as 
untenable  as  his  theory  of  the  immortality  of  the 
unicellulars.  According  to  this  opinion,  the  death  of  the 
histona — both  the  metaphyta  and  metazoa — is  a  pur- 
posive outcome  of  adaptation,  only  introduced  by  se- 
lection when  the  multicellular  organism  has  reached  a 
certain  stage  of  complexit}^  of  structure,  which  is  incom- 
patible with  its  original  immortalit}^  Natural  selection 
v\^ould  thus  kill  the  immortal  and  preserve  only  the 
mortal ;  it  would  interfere  with  the  multiplication  of  the 
immortals  in  the  bloom  of  their  years,  and  only  use  the 
mortal  for  rearing  posterity.  The  curious  conclusions 
which  Weismann  reached  in  developing  this  theory  of 
death,  and  the  striking  contradictions  to  his  own  theory 
of  the  germ-plasm  which  he  fell  into,  have  been  pointed 
out  by  Kassowitz  in  the  forty-ninth  chapter  of  his  Gen- 
eral Biology.  In  my  opinion,  this  paradoxical  theory  of 
death  has  no  more  basis  than  the  germ-plasm  theory  he 
has  ingeniously  connected  with  it.     We  may  admire  the 

IOC 


DEATH 

subtlety  and  depth  of  the  speculations  with  which 
Weismann  has  worked  out  his  elaborate  molecular 
theory.  But  the  nearer  we  get  to  its  foundations  the  less 
solid  we  find  them.  Moreover,  not  one  of  the  many 
supporters  of  the  theory  of  germ-plasm  has  been  able 
to  make  profitable  use  of  it  in  the  twenty  years  since  it 
was  first  published.  On  the  other  hand,  it  has  had  an 
evil  influence  in  so  far  as  it  denied  the  inheriting  of 
acquired  characters,  which  I  hold,  with  Lamarck  and 
Darwin,  to  be  one  of  the  soundest  and  most  indis- 
pensable supports  of  the  theory  of  descent. 

In  discussing  the  question  of  the  real  causes  of  death, 
we  confine  our  attention  to  normal  or  physiological  death 
without  considering  the  innumerable  causes  of  accidental 
or  pathological  death,  by  illness,  parasites,  mishaps,  etc. 
Normal  death  takes  place  in  all  organisms  when  the 
limit  of  the  hereditary  term  of  life  is  reached.  This 
limit  varies  enormously  in  different  classes  of  organisms. 
Many  of  the  unicellular  protophyta  and  protozoa  live 
only  a  few  hours,  others  several  months  or  years;  many 
one-year  plants  and  lower  animals  live  only  a  summer  in 
our  temperate  climate,  and  only  a  few  weeks  or  months 
in  the  arctic  circle  or  on  the  snow-covered  Alps.  On  the 
other  hand,  the  larger  vertebrates  are  not  uncommonly  a 
hundred  years  old,  and  many  trees  live  for  a  thousand 
years.  The  normal  span  of  life  has  been  determined  in 
all  species  in  the  course  of  their  evolution  by  adaptation 
to  special  conditions,  and  has  then  been  transmitted  to 
offspring  by  heredity.  In  the  latter,  however,  it  is  often 
subject  to  considerable  modifications. 

The  organism  has  been  compared,  on  the  modem 
"machine  theory"  of  life,  to  an  artificially  constructed 
mechanism,  or  an  apparatus  in  which  the  human  intelli- 
gence has  put  together  various  parts  for  the  attainment 
of  a  certain  end.  This  comparison  is  inapplicable  to  the 
lowest  organisms,  the  monera,  which  are  devoid  of  such 

101 


THE     WONDERS     OF     LIFE 

a  mechanical  structure.  In  these  primitive  "organisms 
without  organs"  (chromacea  and  bacteria)  the  sole  cause 
of  life  is  the  invisible  chemical  structure  of  the  plasm 
and  the  metabolism  effected  by  this.  As  soon  as  this 
ceases  death  takes  place  {cf.  chapter  ix.).  In  the  case  of 
all  other  organisms  the  comparison  is  useful  in  so  far  as 
the  orderly  co-operation  of  the  various  organs  or  parts 
accomplishes  a  certain  task  by  the  conversion  of  virtual 
into  active  force.  But  the  great  difference  between  the 
two  is  that  in  the  case  of  the  machine  the  regularity  is 
due  to  the  purposive  and  consciously  acting  will  of  man, 
whereas  in  the  case  of  the  organism  it  is  produced  by 
unconscious  natural  selection  without  any  design.  On 
the  other  hand,  the  two  have  another  important  feature 
in  common  in  the  limited  span  of  life  which  is  involved 
in  their  being  used  up.  A  locomotive,  ship,  telegraph, 
or  piano,  will  last  only  a  certain  number  of  years.  All 
their  parts  are  worn  out  by  long  use,  and,  in  spite  of  all 
repairing,  become  at  last  useless.  So  in  the  case  of  all 
organisms,  the  various  parts  are  sooner  or  later  worn 
out  and  rendered  useless;  this  is  equally  true  of  the 
organella  of  the  protist  and  the  organs  of  the  histon. 
It  is  true  that  the  parts  may  be  repaired  or  regenerated; 
but  sooner  or  later  they  cease  to  be  of  service,  and 
become  the  cause  of  death. 

When  we  take  the  idea  of  regeneration,  or  the  re- 
cuperation of  parts  that  have  been  rendered  useless, 
in  the  widest  sense,  we  find  it  to  be  a  universal  vital 
function  of  the  greatest  importance.  The  whole  metab- 
olism of  the  living  organism  consists  in  the  assimilation 
of  plasm,  or  the  replacing  of  the  plasma-particles  which 
are  constantly  used  up  by  dissimilation  {cf.  chapter  x.). 
Verworn  has  given  the  name  of  hiogens  to  the  hypo- 
thetical molecules  of  living  matter — which  I  regard  with 
Hering  as  endowed  with  memory,  and  (1875)  have  called 
plastidules.     He    says:    "The    biogens    are    the    real 

102 


DEATH 

vehicles  of  life.  In  their  constant  decay  and  recon- 
struction consists  the  process  of  life,  which  expresses 
itself  in  the  great  variety  of  vital  phenomena."  The 
relation  of  assimilation  (the  building-up  of  the  biogens) 
to  dissimilation  (the  decay  of  the  biogens)  may  be  ex- 
pressed by  a  fraction  to  which  the  name  hiotoniis  is  given 
a|d.  It  is  of  radical  importance  in  the  various  phenom- 
ena of  life.  The  variations  in  the  size  of  this  fraction 
are  the  cause  of  all  change  in  the  life-expression  of 
every  organism.  When  the  bio  tone  increases,  and  the 
metabolism  quotient  becomes  more  than  one,  we  have 
growth;  when,  on  the  other  hand,  it  falls  below  one, 
and  the  biotone  decreases,  we  have  atrophy,  and  finally 
death.  New  biogens  are  constructed  in  regeneration. 
In  generation  or  reproduction  groups  of  biogens  (as  germ- 
plasm)  are  released  from  the  parent  in  consequence  of 
redundant  growth,  and  form  the  foundation  of  new 
individuals. 

The  phenomena  of  regeneration  are  extremely  varied, 
and  have  of  late  years  been  made  the  subject  of  a  good 
deal  of  comprehensive  experiment,  especially  on  the  side 
of  what  is  called  "mechanical  embryology."  Many  of 
these  experimental  embryologists  have  drawn  far-reach- 
ing conclusions  from  their  somewhat  narrow  experiments, 
and  have  partly  urged  them  as  objections  to  Darwinism. 
They  imagine  that  they  have  disproved  the  theory  of 
selection.  Most  of  these  efforts  betray  a  notable  lack  of 
general  physiological  and  morphological  knowledge.  As 
they  also  generally  ignore  the  biogenetic  law,  and  take 
no  account  of  the  fundamental  correlation  of  embry- 
ology and  stem  history,  we  can  hardly  wonder  that 
they  reach  the  most  absurd  and  contradictory  con- 
clusions. Many  examples  of  this  will  be  found  in  the 
Archiv  fiir  Ent'ivickeliingsniechanik.  When,  however,  we 
make  a  comprehensive  survey  of  the  interesting  field  of 
regeneration  processes,  we  discover  a  continuous  series 

103 


THE    WONDERS    OF    LIFE 

of  development  from  the  simplest  repair  of  plasm  in  the 
unicellular  protists  to  the  sexual  generation  of  the 
higher  histona.  The  sperm-cells  and  ova  of  the  latter 
are  redundant  growth-products,  which  have  the  power 
of  regenerating  the  whole  multicellular  organism.  But 
many  of  the  higher  histona  have  also  the  capacity  to 
produce  new  individuals  by  regeneration  from  detached 
pieces  of  tissue,  or  even  single  cells.  In  the  peculiar 
mode  of  metabolism  and  growth  which  accompanies 
these  processes  of  regeneration,  the  memory  of  the 
plastidule,  or  the  unconscious  retentive  power  of  the 
bio  gens,  plays  the  chief  part  (cf.  my  Perigenesis  of  the 
Plastidule,  1875).  ^^  ^^^  most  primitive  kinds  of  the 
unicellular  protists  we  find  the  phenomena  of  death  and 
regeneration  in  the  simplest  form.  When  an  unnu- 
cleated  moneron  (a  chromaceum  or  bacterium)  divides 
into  two  equal  halves,  the  existence  of  the  dividing 
individual  comes  to  an  end.  Each  half  regenerates 
itself  in  the  simplest  conceivable  way  by  assimilation 
and  growth,  until  it,  in  turn,  reaches  the  size  of  the 
parent  organism.  In  the  nucleated  cells  of  most  of  the 
protophyta  and  protozoa  it  is  more  complicated,  as  the 
nucleus  becomes  active  as  the  central  organ  and  reg- 
ulator of  the  metabolism.  If  an  infusorium  is  cut 
into  two  pieces,  only  one  of  which  contains  the  nucleus, 
this  one  alone  grows  into  a  complete  nucleated  cell;  the 
unnucleated  portion  dies,  being  unable  to  regenerate 
itself. 

In  the  multicellular  body  of  the  tissue-forming  or- 
ganisms we  must  distinguish  between  the  partial  death 
of  the  various  cells  and  the  total  death  of  the  whole 
organism,  or  cell-state,  which  they  make  up.  In  many 
of  the  lower  tissue-plants  and  tissue-animals  the  com- 
munal link  is  very  loose  and  the  centralization  slight. 
Odd  cells  or  groups  of  cells  may  be  set  loose,  without  any 
danger  to  the  life  of  the  whole  histon,  and  grow  into  new 

104 


DEATH 

individuals.  In  many  of  the  algaj  and  liverworts  (even 
in  the  bryopJiylluin,  closely  related  to  the  stone-crop,  or 
scdiim) — as  well  as  in  the  common  fresh-water  polyp, 
hydra,  and  other  polyps — every  bit  that  is  cut  off  is 
capable  of  growing  into  a  complete  individual.  But  the 
higher  the  organization  is  developed  and  the  closer  the 
correlation  of  the  parts  and  their  co-operation  in  the  life 
of  the  centralized  stock  or  person,  the  slighter  we  find 
the  regenerative  faculty  of  the  several  organs.  Even 
then,  however,  many  used-up  cells  may  be  removed  and 
replaced  by  regenerated  new  cells.  In  our  own  human 
organism,  as  in  that  of  the  higher  animals,  thousands  of 
cells  die  every  day,  and  are  replaced  by  new  cells  of  the 
same  kind,  as,  for  instance,  epidermic  cells  at  the  surface 
of  the  skin,  the  cells  of  the  salivary  glands  or  the  mucous 
lining  of  the  stomach,  the  blood-cells,  and  so  on.  On 
the  other  hand,  there  are  tissues  that  have  little  or  noth- 
ing of  this  repairing  power,  such  as  many  of  the  nerve- 
cells,  sense-cells,  muscle-cells,  etc.  In  these  cases  a  num- 
ber of  constant  cell-individuals  remain  with  their  nucleus 
throughout  life,  although  a  used-up  portion  of  their  cell- 
body  may  be  replaced  by  regeneration  from  the  cyto- 
plasm. Thus  our  human  body,  like  that  of  all  the 
higher  animals  and  plants,  is  a  "cell-state"  in  another 
sense.  Every  day,  nay,  every  hour,  thousands  of  its 
citizens,  the  tissue-cells,  pass  away,  and  are  replaced 
by  others  that  have  arisen  by  cleavage  of  similar  cells. 
Nevertheless,  this  uninterrupted  change  of  our  personal- 
ity is  never  complete  or  general.  There  is  always  a 
solid  groundwork  of  conservative  cells,  the  descendants 
of  which  secure  the  further  regeneration. 

Most  organisms  meet  their  death  through  external  or 
accidental  causes — lack  of  sufficient  food,  isolation  from 
their  necessary  environment,  parasites  and  other  enemies, 
accidents  and  disease.  The  few  individuals  who  escape 
these  accidental  causes  of  death  find  the  end  of  life  in 

105 


THE    WONDERS    OF    LIFE 

old  age  or  senility,  by  the  gradual  decay  of  the  organs  and 
dwindling  of  their  functions.  The  cause  of  this  senility 
and  the  ensuing  natural  death  is  determined  for  each 
species  of  organisms  by  the  specific  nature  of  their 
plasm.  As  Kassowitz  has  lately  pointed  out,  the  senility 
of  individuals  consists  in  the  inevitable  increase  in  the 
decay  of  protoplasm  and  the  metaplastic  parts  of  the 
body  which  this  produces.  Each  metaplasm  in  the  body 
favors  the  inactive  break-up  of  protoplasm,  and  so  also 
the  formation  of  new  metaplasms.  The  death  of  the 
cells  follows,  because  the  chemical  energy  of  the  plasm 
gradually  falls  off  from  a  certain  height,  the  acme,  of 
life.  The  plasm  loses  more  and  more  the  power  to 
replace  by  regeneration  the  losses  it  sustains  by  the 
vital  functions.  As,  in  the  mental  life,  the  receptivity  of 
the  brain  and  the  acuteness  of  the  senses  gradually 
decay,  so  the  muscles  lose  their  energy,  the  bones 
become  fragile,  the  skin  dry  and  withered,  the  elasticity 
and  endurance  of  the  movements  decrease.  All  these 
normal  processes  of  senile  decay  are  caused  by  chemical 
changes  in  the  plasm,  in  which  dissimilation  gains  con- 
stantly on  assimilation.  In  the  end  they  inevitably  lead 
to  normal  death. 

While  the  gradual  decay  of  the  bodily  forces  and  the 
senile  degeneration  of  the  organs  must  necessarily  cause 
the  death  of  the  soundest  organism  in  the  end,  the  great 
majority  of  men  pass  away  through  illness  long  before 
this  normal  term  of  life  is  reached.  The  external  causes 
of  this  are  the  attacks  of  enemies  and  parasites,  acci- 
dents, and  unfavorable  conditions  of  life.  These  cause 
changes  in  the  tissues  and  their  component  cells,  which 
first  occasion  the  partial  death  of  particular  sections,  and 
then  the  total  death  of  the  whole  individual.  The  modi- 
fications of  the  living  matter  which  produce  disease  and 
premature  death  are  called  necrobioses.  They  consist 
partly  of  histolyses — that  is  to  say,  degeneration  of  the 

io6 


DEATH 

cells  by  atrophy,  dissolution,  withering  (mortification), 
or  colliquation;  and  partly  of  mctaplasmosisms,  or  meta- 
morphoses of  the  plasm — fatty,  mucous,  chalky,  or 
amyloid  metamorphoses  of  the  cells.  It  was  the  great 
merit  of  Rudolph  Virchow  that  he  proved,  in  his  epoch- 
making  Cellular  Pathology  (1858),  that  all  diseases  in 
man  and  other  organisms  may  be  reduced  to  such  modi- 
fications of  the  cells  which  make  up  the  tissues.  Hence 
disease,  with  its  pain,  is  a  physiological  process,  a  life 
under  injurious  and  dangerous  conditions.  As  in  all 
normal  vital  phenomena,  so  in  abnormal  or  pathological, 
the  ultimate  ground  must  be  sought  in  the  physical  and 
chemical  processes  in  the  plasm.  Pathology  is  a  part  of 
physiology.  This  discovery  has  cut  the  ground  from 
under  the  older  notion  of  disease  as  a  special  entity,  a 
devil,  or  a  divine  punishment. 

The  natural  physical  explanation  of  death,  which  has 
been  made  possible  by  modern  physiology  and  pathology, 
has  shattered,  not  only  all  the  old  superstitious  ideas 
about  disease  and  death,  but  also  a  number  of  important 
metaphysical  dogmas  which  built  upon  them.  Such 
was,  for  instance,  the  naive  belief  in  a  conscious  Provi- 
dence, controlling  the  fate  of  individuals  and  determining 
their  death.  I  do  not  fail  to  appreciate  the  great  sub- 
jective value  which  such  a  trust  in  a  protecting  Provi- 
dence has  for  men  amid  their  countless  dangers.  We  may 
envy  the  childish  temper  for  the  confidence  and  hope 
which  it  derives  from  this  belief.  But  as  we  do  not  seek 
to  have  our  emotions  gratified  by  poetic  fictions,  we  are 
bound  to  point  out  that  reason  cannot  detect  the  shadow 
of  a  proof  of  the  existence  and  action  of  this  conscious 
Providence,  or  "loving  Father  in  heaven."  We  read 
daily  in  our  journals  of  accidents  and  crimes  of  all  kinds 
that  cause  the  unexpected  death  of  happy  human  beings. 
Every  year  we  read  with  horror  the  statistics  of  the 
thousands  of  deaths  from  shipwreck  and  railway  acci- 

107 


THE    WONDERS    OF    LIFE 

dents,  earthquakes  and  landslips,  wars  and  epidemics. 
And  then  we  are  asked  to  believe  in  a  loving  Providence 
that  has  decreed  the  death  of  each  of  these  poor  mortals! 
We  are  asked  to  console  ourselves  in  face  of  the  tragedy 
with  the  hollow  phrases:  "God's  will  be  done,"  or 
"God's  ways  are  wonderful."  Simple  children  and  dull 
believers  may  soothe  themselves  with  such  phrases. 
They  no  longer  impose  on  educated  people  in  the 
twentieth  century,  who  prefer  a  full  and  fearless  knowl- 
edge of  the  truth. 

When  our  monistic  and  rational  conception  of  death  is 
described  as  dreary  and  hopeless,  we  may  answer  that 
the  prevalent  dualistic  view  is  merely  an  outcome  of 
hereditary  habits  of  thought  and  mystic  training  in  early 
youth.  When  these  are  displaced  by  progressive  culture 
and  science,  it  will  be  clear  that  man  has  lost  nothing, 
but  gained  much,  as  regards  his  life  on  earth.  Con- 
vinced that  there  is  no  eternal  life  awaiting  him,  he  will 
strive  all  the  more  to  brighten  his  life  on  earth  and 
rationally  improve  his  condition  in  harmony  with  that  of 
his  fellows.  If  it  is  objected  that  then  everything  will 
depend  on  mere  "chance,"  instead  of  being  controlled 
by  a  conscious  Providence  or  a  moral  order  of  the  world, 
I  must  refer  the  reader  for  my  reply  to  the  close  of  the 
fourteenth  chapter  of  the  Riddle,  where  I  have  dealt 
with  fate,  providence,  end,  aim,  and  chance.  And  if  it 
is  further  claimed  that  our  realistic  view  of  life  leads  to 
pessimism,  there  is  no  better  ground  for  such  an  ac- 
cusation. 

I  have  given,  in  the  eleventh  chapter  of  the  Riddle,  the 
scientific  reasons  which  forbid  us  to  accept  the  personal 
immortality  of  the  soul.  But  as  the  most  vehement 
attacks  have  been  made  on  this  chapter  by  meta- 
physicians of  the  prevailing  school  and  by  Christian 
theologians,  I  must  return  to  the  question  here.  I  am 
convinced,  from  numbers  of  letters  I  have  received  an4 

io8 


DEATH 

conversation  with  educated  people  of  all  classes,  that 
no  other  dogma  is  so  firmly  established  and  highly 
valued  as  athanatism,  or  the  belief  in  personal  im- 
mortality. Most  men  will  not  give  up  at  any  price 
the  hope  that  a  better  life  awaits  them  beyond  the 
grave,  which  will  compensate  them  for  all  the  pain  and 
suffering  they  endure  here.  In  the  picturing  of  this 
future  life  the  mediaeval  geocentric  idea  still  forms  the 
chief  feature.  Troelslund  has  shown,  in  his  Idea  of 
Heaven  and  of  the  World,  how  this  theory  still  dominates  , 
the  metaphysics  of  the  majority  of  men;  in  spite  of 
Copernicus  and  Laplace,  heaven  is  still  for  most  people 
the  semicircular  blue  glass  bell  that  overarches  the 
earth.  We  still  hear  the  praises  of  our  life  in  this  heaven 
sung  daily  in  sermons  and  speeches  and  festive  orations. 
The  orator  extends  his  right  hand  "upward"  to  the 
infinite  starry  space  of  heaven,  forgetting  that  the  radius 
of  the  direction  he  is  pointing  towards  changes  every 
second,  and  in  twelve  hours  reaches  the  precisely  op- 
posite direction,  and  becomes  "downward."  Other  be- 
lievers endeavor  to  be  still  more  concrete,  and  point  out 
definite  celestial  bodies  as  the  homes  of  immortal  souls. 
Modern  cosmology,  astronomy,  and  geology  entirely 
exclude  these  pretty  fictions  from  science;  and  modern 
psychology,  physiology,  ontogeny,  and  phylogeny  rigor-  / 

ously  refuse  an  inch  of  ground  for  athanatism.  \ 

Optimism  regards  the  world  on  its  good  and  bright  and 
admirable  side:  pessimism  looks  to  the  shades  and 
tragedies  of  life.  In  some  philosophic  and  religious 
systems  one  or  other  of  these  tendencies  is  consistently 
and  exclusively  worked  out;  but  in  most  systems  the 
two  are  mingled.  Pure  and  consistent  realism  is  I 
generally  neither  optimistic  nor  pessimistic.  It  takes 
the  world  as  it  is,  a  unified  whole,  the  nature  of  which 
is  neither  good  nor  bad.  Dualistic  idealism,  however, __ 
generally  combines  the  two,  and  distributes  them  be- 

109 


THE    WONDERS    OF    LIFE 

tween  its  two  worlds ;  it  describes  this  world  as  a  "  vale  of 
tears,"  and  the  next  as  a  glorious  city  of  joy  and  hap- 
piness. This  view  is  a  conspicuous  feature  in  most 
of  the  dualistic  religions,  and  has  still  a  considerable 
influence,  both  practically  and  theoretically,  on  the 
minds  of  educated  people. 

The  founder  of  systematic  optimism  was  Gottfried 
Leibnitz,  whose  philosophy  sought  to  achieve  an  in- 
genious harmony  between  divergent  systems,  but  is 
reall}^  a  form  of  dynamism,  or  a  monism  somewhat  akin 
to  the  energism  of  Ostwald.  Leibnitz  gave  a  compen- 
dious statement  of  his  system  in  his  Monadology  {1^14.). 
He  taught  that  the  world  consists  of  an  infinite  number 
of  monads  (which  almost  correspond  to  our  psychic 
atoms) ,  but  this  pluralism  was  converted  into  a  monism 
by  making  God,  as  the  central  monad,  bind  all  to- 
gether in  a  substantial  imity.  In  his  Theodicy  (17 10) 
he  taught  that  God  (the  "all-wise,  all-good,  and  al- 
mighty creator  of  the  world")  had  with  perfect  con- 
sciousness created  "the  best  of  all  possible  worlds"; 
that  his  infinite  goodness,  w^isdom,  and  power  are  seen 
everywhere  in  the  pre-established  harmony  of  things; 
but  that  the  individual  human  being,  and  humanity 
taken  as  a  whole,  have  only  a  limited  capacity  for 
development.  The  man  who  knows  the  real  features 
of  the  world,  who  has  honestly  confronted  the  tragic 
struggle  for  life  that  rules  throughout  living  nature, 
who  has  sympathy  for  the  infinite  sum  of  misery  and 
want  of  every  kind  in  the  life  of  men,  can  scarcely 
understand  how  an  acute  and  informed  thinker  like 
Leibnitz  could  entertain  such  optimism  as  this.  It 
would  be  more  intelligible  in  the  case  of  a  one-sided  and 
nebulous  metaphysician  like  Hegel,  who  held  that  "all 
that  is  real  is  rational  and  all  that  is  rational  is  real." 

Pessimism  is  the  direct  opposite  of  systematic  opti- 
mism.    While  the  one  holds  the  universe  to  be  the  best, 

no 


DEATH 

the  other  regards  it  as  the  worst,  of  all  possible  worlds. 
This  pessimistic  conception  has  found  expression  in  the 
oldest  and  most  popular  religions  of  Asia,  Brahmanism 
and  Buddhism.  Both  these  Hindoo  religions  were 
orginally  pessimistic,  and  at  the  same  time  atheistic 
and  idealistic.  Schopenhauer  especially  pointed  out 
this,  declaring  that  they  were  the  most  perfect  of  all 
religions,  and  importing  their  leading  ideas  into  his  own 
system.  He  considers  it  "  a  glaring  absurdity  to  attempt 
to  prove  this  miserable  world  the  best  of  all  possible 
ones — this  cock-pit  of  tortured  and  suffering  beings,  who 
can  only  survive  by  destroying  one  another,  in  which 
the  capacity  for  pain  grows  with  knowledge,  and  so 
reaches  its  height  in  man.  Truly  optimism  cuts  so 
sorry  a  figure  in  this  theatre  of  sin,  suffering,  and  death 
that  we  should  have  to  regard  it  as  a  piece  of  sarcasm  if 
Hume  had  not  given  us  an  explanation  of  its  origin  (the 
wish  to  flatter  God  and  hope  for  some  result  from  it). 
To  the  palpable  sophistry  of  Leibnitz,  who  would  prove 
this  world  the  best  of  all  possible,  we  can  oppose  a  strict 
and  honest  proof  that  it  is  the  worst  of  all  possible." 
However,  neither  Schopenhauer  nor  the  most  important 
of  modem  pessimists,  Edward  Hartmann,  has  drawn  the 
strict  practical  conclusion  from  pessimism.  That  would 
be  to  deny  the  will  to  live,  and  put  an  end  to  suffering  by 
suicide. 

The  mention  of  suicide  as  the  logical  consequence  of 
pessimism  may  serve  as  an  occasion  to  glance  at  the 
curious  and  contradictory  views  that  are  expressed  about 
it.  There  are  few  problems  of  life  (apart  from  immor- 
tality and  the  freedom  of  the  will)  on  which  such  absurd 
and  contradictory  things  have  been  said  even  down  to 
our  own  time.  The  theist  who  regards  life  as  a  gift  of 
God  may  hesitate  to  reject  or  return  it — although  the 
offering  of  one's  self  as  a  victim  for  other  men  is  consid- 
ered a  high  virtue.     Most  educated  people  still  look  upon 

III 


THE    WONDERS    OF    LIFE 

suicide  as  a  great  sin,  and  in  some  countries  (such  as 
England)  the  attempt  is  punished  by  law.  In  the  Middle 
Ages,  when  a  hundred  thousand  men  were  burned  alive 
for  heresy  or  witchcraft,  suicides  were  punished  by  a 
disgraceful  burial.  As  Schopenhauer  says:  "Clearly 
there  is  nothing  in  the  world  to  which  a  man  has  a 
plainer  right  than  his  own  life  and  person.  It  is  simply 
ridiculous  for  criminal  justice  to  deal  with  suicide." 
The  advance  of  embryology  in  the  last  thirty  years  has 
made  it  clear  that  the  individual  life  of  a  man  (and  all 
other  vertebrates)  begins  at  the  moment  when  the  male 
sperm-cell  and  the  maternal  ovum  coalesce.  In  this 
blind  chance  plays  an  important  part,  as  in  so  many 
other  important  aspects  of  life — taking  "chance"  in  the 
scientific  sense,  which  I  have  explained  in  chapter  xiv.  of 
the  Riddle.  Hence,  the  real  cause  of  personal  existence 
is  not  the  favor  of  the  Almighty,  but  the  sexual  love  of 
one's  earthly  parents;  very  often  this  consequence  of  the 
act  of  love  has  been  anything  but  desired.  If,  then,  the 
circumstances  of  life  come  to  press  too  hard  on  the  poor 
being  who  has  thus  developed,  without  any  fault  of  his, 
from  the  fertilized  ovum — if,  instead  of  the  hoped-for 
good,  there  come  only  care  and  need,  sickness  and  misery 
of  every  kind — he  has  the  unquestionable  right  to  put  an 
end  to  his  sufferings  by  death.  Every  religion  assents  to 
this  under  certain  conditions,  even  Christianity  when  it 
says:  "If  thine  eye  scandalize  thee,  cast  it  from  thee." 
It  is  true  that  the  conventional  morality  condemns 
suicide  under  any  circumstances;  but  the  reasons  it 
alleges  are  ridiculously  slight,  and  are  not  improved  by 
having  the  mantle  of  religion  wrapped  about  them. 

The  voluntary  death  by  which  a  man  puts  an  end  to 
intolerable  suffering  is  really  an  act  of  redemption.  We 
should,  therefore,  describe  it  as  self -redemption,  and  look 
on  it  with  Christian  sympathy,  not  brand  it  pharisaically 
as  "self-murder."     As  a  fact,  this  contemptuous  phrase 

112 


DEATH 

has  no  meaning,  since  murder  is  the  taking  away  of  a 
man's  life  against  his  will,  while  the  suicide  dies  volun- 
tarily. Hence,  he  usually  deserves  our  sympathy,  not 
contempt,  and  certainly  not  punishment.  Our  conven- 
tional morality  is,  as  so  often  happens,  full  of  senseless 
contradictions.  Modern  states  have  introduced  con- 
scription; they  demand  that  every  citizen  shall  give  up 
his  life  for  his  country  on  command,  and  kill  as  many 
other  men  as  he  can  (an  admirable  commentary  on  the 
Scriptural  "Love  your  enemies")  for  some  political 
reason  or  other.  But  they  never  secure  to  each  citizen 
the  means  of  honorable  existence  and  free  development 
of  his  personality — not  even  the  right  to  work  by  which 
he  may  maintain  himself  and  his  family. 

I  fully  recognize  the  advance  that  social  politics  has 
made  in  improving  the  conditions  of  the  poorer  classes, 
the  promotion  of  hygiene  and  education  and  the  bodily 
and  mental  welfare  of  citizens ;  but  we  are  still  very  far 
from  the  attainable  ideal  of  general  prosperity  and  happi- 
ness which  reason  dictates  to  every  civilized  nation. 
Misery  and  want  are  increasing  among  the  poor,  as 
the  division  of  labor  and  over-population  increase. 
Thousands  of  strong  and  active  men  come  to  grief  every 
year  without  any  fault  of  theirs,  often  precisely  because 
they  were  quiet  and  honest;  thousands  are  hungry 
because,  with  the  best  will  in  the  world,  they  cannot  find 
work;  thousands  are  sacrificed  to  the  heartless  demands 
of  our  iron  age  of  machinery  with  its  exacting  technical 
and  industrial  requirements.  On  the  other  hand,  we  see 
thousands  of  contemptible  characters  prospering  because 
they  have  been  able  to  deceive  their  fellows  by  un- 
scrupulous speculations,  or  because  they  have  flattered 
and  served  the  higher  authorities.  It  is  no  wonder  that 
the  statistics  of  suicide  increase  so  much  in  the  more 
civilized  communities.  No  feeling  man  who  has  any 
real  "Christian  love  of  his  neighbor"  will  grudge  his 
8  113 


THE    WONDERS    OF    LIFE 

suffering  brother  the  eternal  rest  and  the  freedom  from 
pain  which  he  has  obtained  by  his  self -redemption. 

The  seventh  petition  of  the  Lord's  Prayer,  which  is 
repeated  daily  by  millions  of  Christians,  is:  "Deliver 
us  from  evil."  Luther  explains  this  as  a  prayer  to  be 
saved  "from  all  evil  of  body  and  soul"  in  this  life  and 
the  next.  When  we  consider  this  in  the  light  of  our 
monistic  principles,  we  have  naturally  to  set  aside  the 
superstitious  ideas  of  the  Middle  Ages  regarding  the 
future  life,  and  deal  only  with  the  petition  as  regards 
this  life.  The  number  and  variety  and  gravity  of  these 
evils  have  grown  in  civilized  communities  in  the  nine- 
teenth century,  notwithstanding  all  the  progress  we 
have  made  in  art  and  science  and  the  rational  reform  of 
our  personal  and  social  life.  Civilization  has  gained  in- 
finitely in  value  by  the  change  we  have  made  in  our  con- 
ceptions of  time  and  space  in  this  age  of  steam  and 
electricity.  We  can  make  our  domestic  and  public  life 
much  pleasanter,  and  avail  ourselves  of  a  far  greater 
number  of  luxuries,  than  was  possible  to  our  grand- 
fathers a  hundred  years  ago.  But  all  this  has  caused  a 
much  greater  expenditure  of  nerve-energy.  The  brain 
has  to  bear  a  much  greater  strain,  and  is  worn  out  earlier, 
the  body  is  more  stimulated  and  overworked  than  it 
was  a  hundred  years  ago.  Many  diseases  of  modern 
civilization  are  making  appalling  progress;  neurasthenia, 
especially,  and  other  diseases  of  the  nerves,  carry  off 
more  victims  every  year.  Our  asylums  grow  bigger  and 
more  numerous  every  year,  and  we  have  sanatoria  on 
every  side  in  which  the  baited  victim  of  modern  civiliza- 
tion seeks  refuge  from  his  evils.  Some  of  these  evils  are 
quite  incurable,  and  the  sufferers  have  to  meet  a  certain 
death  in  terrible  pain.  Many  of  these  poor  creatures 
look  forward  to  their  redemption  from  evil  and  the  end 
of  their  miserable  lives.  The  important  question  arises 
whether,  as  compassionate  men,  we  should  be  justified 

114 


DEATH 

in  carrying  out  their  wish  and  ending  their  sufferings  by 
a  painless  death. 

This  question  is  of  great  importance,  both  in  practical 
philosophy  and  in  juridical  and  medical  practice,  and,  as 
opinions  differ  very  much  on  the  subject,  it  seems 
advisable  to  deal  with  it  here.  I  start  from  my  own 
personal  opinion,  that  sympathy  is  not  only  one  of  the 
noblest  and  finest  functions  of  the  human  brain,  but 
also  one  of  the  first  conditions  of  the  social  life  of  the 
higher  animals.  The  precepts  of  Christian  charity 
which  the  gospels  rightly  place  in  the  very  foreground 
of  morality,  were  not  first  discovered  by  Christ,  but  they 
were  successfully  urged  by  him  and  his  followers  at  a 
time  when  refined  selfishness  threatened  the  Roman 
civilization  with  decay.  These  natural  principles  of 
sympathy  and  altruism  had  arisen  thousands  of  years 
before  in  human  society,  and  are  even  found  among  all 
the  higher  animals  that  live  a  social  life.  They  have 
their  first  roots  in  the  sexual  reproduction  of  the  lower 
animals,  the  sexual  love  and  the  care  of  the  young  on 
which  the  maintenance  of  the  species  depends.  Hence] 
the  modern  prophets  of  pure  egoism,  Friedrich  Nietzsche, 
Max  Stirner,  etc.,  commit  a  biological  error  when  they 
would  substitute  their  morality  of  the  strong  for  uni- 
versal charity,  and  when  they  ridicule  sympathy  as  a 
weakness  of  character  or  an  ethical  blunder  of  Christian- 
ity. It  is  just  in  its  insistence  on  sympathy  that  the 
Christian  teaching  is  most  valuable,  and  this  part  of  its 
system  will  survive  long  after  its  dogmas  have  sunk  into 
oblivion.  However,  this  lofty  duty  must  not  be  con- 
fined to  men,  but  extended  to  "our  relations,"  the 
higher  vertebrates,  and,  in  fact,  to  all  animals  whose 
brain-organization  seems  to  point  to  the  possession  of 
sensation  and  a  consciousness  of  pleasure  and  pain. 
Thus,  for  instance,  in  the  case  of  the  domestic  animals 
which  we  use  daily  in  our  service,  and  which  have  an 

115 


THE    WONDERS    OF    LIFE 

undoubted  psychic  affinity  to  ourselves,  we  must  take 
care  to  increase  their  pleasures  and  mitigate  their 
sufferings.  Faithful  dogs  and  noble  horses,  with  which 
we  have  lived  for  years  and  which  we  love,  are  rightly 
put  to  death  and  relieved  from  pain  when  they  fall  hope- 
lessly ill  in  old  age.  In  the  same  way  we  have  the 
right,  if  not  the  duty,  to  put  an  end  to  the  sufferings 
of  our  fellow-men.  Some  severe  and  incurable  disease 
makes  life  unbearable  for  them,  and  they  ask  for  re- 
demption from  evil.  However,  medical  men  hold 
very  different  opinions  on  the  matter,  as  I  have  found 
in  conversation  with  them.  Many  experienced  phy- 
sicians, who  practise  their  profession  in  a  spirit  of 
sympathy  and  without  dogmatic  prejudice,  have  no 
scruple  about  cutting  short  the  sufferings  of  the  incura- 
ble by  a  dose  of  morphia  or  cyanide  of  potassium  when 
they  desire  it;  very  often  this  painless  end  is  a  blessing 
both  to  the  invalids  and  their  families.  However,  other 
physicians  and  most  jurists  are  of  opinion  that  this  act 
of  sympathy  is  not  right,  or  is  even  a  crime;  that  it  is 
the  duty  of  the  physician  to  maintain  the  life  of  his 
patients  as  long  as  he  can  in  all  circumstances.  I 
should  like  to  know  why. 

While  I  am  dealing  with  this  important  and — for  the 
medical  conscience — difficult  question  of  social  ethics,  I 
may  take  the  opportunity  to  consider  the  general  attitude 
of  physicians  to  the  monistic  philosophy.  It  is  now  half 
a  century  since  I  visited  the  wards  in  the  Julius  hospital 
at  Wiirtzburg  as  a  medical  student.  It  is  true  that — 
happily  for  me  and  m}^  patients! — I  practised  the  profes- 
sion only  for  a  short  time  after  I  had  passed  my  examina- 
tions in  1857;  but  the  thorough  acquaintance  with  the 
human  organism,  its  anatomic  structure  and  physio- 
logical functions,  which  I  then  obtained  has  been  of  in- 
calculable service  to  me.  I  owe  to  it  not  only  the  solid 
empirical  foundation  of  the  special  study  of  my  life, 

116 


DEATH 

zoology,  but  also  the  monistic  tendency  of  my  whole 
system.  As  the  medical  training  in  its  widest  sense  in- 
cludes anthropology  —  and  so  should  include  psychol- 
ogy also — its  value  for  speculative  philosophy  cannot  be 
exaggerated.  The  scholastic  metaphysicians  who  still 
regard  the  chairs  of  philosophy  at  our  universities  as 
their  monopoly  would  have  avoided  most  of  their 
dualistic  errors  if  they  had  had  a  thorough  training  in 
human  anatomy,  physiology,  ontogeny,  and  phylogeny. 
Even  pathology,  the  science  of  the  diseased  organism, 
is  very  instructive  for  the  philosopher.  The  psychologist 
especially  acquires,  by  the  study  of  mental  disease  and 
the  visiting  of  the  asylum  wards,  a  profound  insight  into 
the  mental  life  which  no  speculative  philosophy  could 
give  him.  There  are  few  experienced  and  thoughtful 
physicians  who  retain  the  conventional  belief  in  the 
immortality  of  the  soul  and  God.  What  would  the 
immortal  soul  do  on  the  other  side  of  eternity  when 
it  is  already  utterly  ruined  in  this  life,  or  was  even 
bom  as  an  idiot?  How  can  a  just  God  condemn  the 
criminal  to  the  fires  of  hell  when  he  himself  has  tainted 
the  man  with  an  hereditary  bias,  or  has  placed  him 
in  an  environment  in  which,  seeing  the  absence  of 
free-will,  crime  was  a  necessity  for  him?  And  how 
can  this  all-loving  God  answer  for  the  immeasurable 
sum  of  want  and  miser}^  and  pain  and  unhappiness, 
which  he  sees  accumulated  before  him  every  year  in  the 
lives  of  families  and  states,  cities  and  hospitals?  It  is 
no  wonder  that  the  old  saying  ran:  Ubi  ires  medici,  duo 
stmt  athei  (Of  three  doctors  two  are  sure  to  be  atheists). 
One  of  my  medical  colleagues  was  an  old,  experienced, 
and  sympathetic  physician  who  had  travelled  all  over  the 
world,  and  had  then,  as  director  of  a  large  hospital,  been 
a  close  witness  of  the  sufferings  of  humanity.  Religiously 
educated  by  pious  parents,  and  endowed  with  keen  sensi- 
tiveness,  he  was,   after  long   struggles,   forced   by   his 

117 


THE    WONDERS    OF    LIFE 

medical  studies  to  part  with  the  faith  of  his  boyhood — 
like  myself,  in  his  twenty-first  year.  We  were  talking 
about  the  great  mysteries  of  life  shortly  before  his  death, 
and  he  said  to  me:  "I  have  been  unable  to  reconcile 
belief  in  the  immortality  of  the  soul  and  the  freedom  of 
the  will  with  my  psychological  experiences,  and  I  have 
been  just  as  unable  to  discover  throughout  the  whole 
world  a  single  trace  of  a  moral  order  or  a  beneficent 
providence.  If  it  is  true  that  an  intelligent  Deity  rules 
the  world,  he  cannot  be  a  God  of  love,  but  an  all-power- 
ful demon,  whose  constant  entertainment  is  an  eternal 
and  merciless  play  of  being  and  becoming,  building  up 
and  destroying."  However,  we  do  still  find  here  and 
there  informed  and  intelligent  physicians  who  adhere 
to  the  three  central  dogmas  of  metaphysics — a  proof  of 
the  immense  power  of  dogmatic  tradition  and  religious 
prejudice. 

We  must  class  as  a  traditional  dogma  the  widespread 
belief  that  man  is  bound  under  all  circumstances  to 
maintain  and  prolong  life,  even  when  it  has  become 
utterly  useless — a  source  of  pain  to  the  incurable  and 
of  endless  trouble  to  his  friends.  Hundreds  of  thousands 
of  incurables — lunatics,  lepers,  people  with  cancer,  etc. 
— are  artificially  kept  alive  in  our  modem  communities, 
and  their  sufferings  are  carefully  prolonged,  without  the 
slightest  profit  to  themselves  or  the  general  body.  We 
have  a  strong  proof  of  this  in  the  statistics  of  lunacy 
and  the  growth  of  asylums  and  nerve-sanatoria.  In 
Prussia  alone  there  were  5 1 ,048  lunatics  cared  for  in  the 
asylums  (six  thousand  in  Berlin)  in  1890;  more  than 
one-tenth  of  them  were  quite  incurable  (four  thousand 
of  them  suffering  from  paresis).  In  France,  in  187 1, 
there  were  49,589  in  the  asylums  (or  1.38  per  thousand 
of  the  population),  and  in  1888  there  were  70,443  (or 
1.82  per  thousand) ;  thus,  in  the  course  of  seventeen  years, 
the  absolute  number  of  the  unsound  rose  nearly  30  per 

118 


DEATH 

cent.  (29.6),  while  the  total  population  only  increased 
5.6  per  cent.  In  our  day  the  number  of  lunatics  in 
civilized  countries  is,  on  the  average,  five-sixths  per 
thousand.  If  the  total  population  of  Europe  is  put 
at  three  hundred  and  ninety  to  four  hundred  millions, 
we  have  at  least  two  million  lunatics  among  them,  and 
of  these  more  than  two  hundred  thousand  are  incurable. 
What  an  enormous  mass  of  suffering  these  figures  in- 
dicate for  the  invalids  themselves,  and  what  a  vast 
amount  of  trouble  and  sorrow  for  their  families,  what 
a  huge  private  and  public  expenditure!  How  much 
of  this  pain  and  expense  could  be  spared  if  people 
could  make  up  their  minds  to  free  the  incurable  from 
their  indescribable  torments  by  a  dose  of  morphia! 
Naturally  this  act  of  kindness  should  not  be  left  to  the 
discretion  of  an  individual  physician,  but  be  determined 
by  a  commission  of  competent  and  conscientious 
medical  men.  So,  in  the  case  of  other  incurables  and 
great  sufferers  (from  cancer,  for  instance),  the  "re- 
demption from  evil"  should  only  be  accomplished  by 
a  dose  of  some  painless  and  rapid  poison  when  they 
have  expressed  a  deliberate  wish  (to  be  afterwards 
juridically  proved)  for  this,  and  under  the  control  of  an 
authoritative  commission. 

The  ancient  Spartans  owed  a  good  deal  of  their 
famous  bravery,  their  bodily  strength  and  beauty,  as  well 
as  their  mental  energy  and  capacity,  to  the  old  custom  of 
doing  away  with  new-born  children  who  were  bom 
weakly  or  crippled.  We  find  the  same  custom  to-day 
among  many  savage  races.  When  I  pointed  out  the 
advantages  of  this  Spartan  selection  for  the  improve- 
ment of  the  race  in  1868  (chapter  vii.  of  the  History  of 
Creation)  there  was  a  storm  of  pious  indignation  in  the 
religious  journals,  as  always  happens  when  pure  reason 
ventures  to  oppose  the  current  ]jrejudices  and  traditional 
beliefs.     But  I  ask:  What  good  does  it  do  to  humanity 

119 


THE    WONDERS    OF    LIFE 

to  maintain  artificially  and  rear  the  thousands  of 
cripples,  deaf-mutes,  idiots,  etc.,  who  are  born  every 
year  with  an  hereditary  burden  of  incurable  disease? 
Is  it  not  better  and  more  rational  to  cut  off  from  the 
first  this  unavoidable  misery  which  their  poor  lives  will 
bring  to  themselves  and  their  families  ?  It  is  no  use  to 
reply  that  religion  forbids  it.  Christianity  also  bids  us 
give  up  our  life  for  our  brethren,  and  to  cast  it  from  us 
when  it  hurts  us — that  is  to  say,  when  it  only  causes 
useless  pain  to  us  and  our  friends.  The  truth  is,  the 
opposition  is  only  due  to  sentiment  and  the  power  of 
conventional  morality — that  is  to  say,  to  the  hereditary 
bias  which  is  clothed  in  early  youth  with  the  mantle  of 
religion,  however  irrational  and  superstitious  be  its 
foundation.  Pious  morality  of  this  sort  is  often  really 
the  deepest  immorality.  "Laws  and  rights  creep  on 
like  an  eternal  sickness;"  this  is  equally  true  of  the 
social  customs  and  morals  on  which  laws  and  rights  are 
founded.  Sentiment  should  never  be  allowed  to  usurp 
the  place  of  reason  in  these  weighty  ethical  questions. 
As  I  pointed  out  in  the  first  chapter  of  the  Riddle,  sen- 
timent is  a  very  amiable,  but  a  very  dangerous,  function 
of  the  brain.  It  has  no  more  to  do  with  the  attainment 
of  the  truth  than  what  is  called  revelation.  That  is 
well  seen  in  Kant's  dualism,  for  his  nmndtis  intclligihilis 
is  essentially  an  outcome  of  his  religious  sentimentality 


I 

PLASM 

Plasm  is  the  universal  living  substance — Definition  of  proto- 
plasm, chemically  and  morpholoi^ically — Physical  character 
— Viscous  condition — Chemical  analysis — Colloid  character 
of  albumin — Albuminoid  molecules — Eleinentary  structure 
of  plasm — Work  of  plasm — Protoplasm  and  metaplasm — 
Structures  of  metaplasm — Frothy  structure — Skeletal  struct- 
ure —  Fibrous  structure  —  Granular  structure  —  Molecular 
structure  —  Plasma  molecules  —  Plastidules  and  biogens  — 
Micella  and  biophora  —  Caryoplasm  and  cytoplasm  — 
Nuclear  matter — Chromatin  and  achromin — Nucleolus  and 
centrosoma — Caryotheka  and  caryolymph — Cellular  matter 
- — Plasma  products — Internal  plasma  products — External 
plasma  products — Cell  membranes — Intercellular  matter— 
Cuticular  matter. 

BY  plasm,  in  the  widesJLseasc  of  the  word,  we  mean 
the  living_„matter,-  or  all  bodies  that  are  found  to 
constitute  the  material  foundations  of  the  phenomena  of 
life.  It  is  usual  to  give  this  matter  the  name  of  proto- 
plasm; but  this  older  and  historically  important  designa- 
tion has  suffered  so  many  changes  of  meaning  through 
the  variety  of  its  applications  that  it  is  better  now  to 
use  it  only  in  the  narrower  sense.  Moreover,  recent 
research  on  protoplasm  has  been  greatly  developed, 
and  several  new  names  have  been  invented,  which  are 
formed  from  the  word  "plasm"  with  a  qualifying  prefix. 
These  are  special  varieties  of  the  general  idea  of  plasm, 
or  special  modifications  of  the  general  matter,  such  as 
metaplasm,  archiplasm,  and  so  on. 

The  botanist,   Hugo  Mohl,  who  first  introduced   the 

121 


THE    WONDERS    OF    LIFE 

name  "protoplasm"  in  1846,  used  it  to  designate  a  part 
of  the  contents  of  the  ordinary  plant-cell — namely,  the 
viscous  matter  that  Schleiden  called  ''cell-mucus,"  which 
is  found  on  the  inner  surface  of  the  cell-wall,  and  often 
forms  a  varying  net-work  or  skeleton  in  the  watery 
fluid  in  the  cell,  and  exhibits  characteristic  movements. 
Mohl  gave  the  name  of  "primordial  skin"  to  this  im- 
portant wall-layer  (the  chief  element  of  the  plant-cell), 
and  called  the  material  of  it,  as  being  chemically  dif- 
ferent from  the  other  parts  of  the  cell,  protoplasm — 
that  is  to  say,  the  first  (proton)  or  earliest  formation  of 
the  organism.  It  is  important  to  notice  that  Mohl,  the 
author  of  the  name,  conceived  it  in  a  purely  chemical, 
not  a  morphological,  sense,  like  Oscar  Hertwig  and  other 
recent  cytologists.  I  intend  to  retain  this  early  chemical 
idea  of  protoplasm — or,  briefly,  plasm.  It  was  also  taken 
in  this  sense  by  Max  Schultze,  who  pointed  out  (in  i860) 
its  extreme  significance  and  wide  distribution  in  all 
living  cells,  and  introduced  an  important  reform  of  the 
cell-theory  which  we  will  see  later. 

The  raixing  of  the  chemical  and  the  morphological 
ideas  of  protoplasm  has  been  very  mischievous  in  recent 
biology,  and  has  led  to  great  confusion.  It  generally 
comes  from  a  failure  to  formulate  clearly  the  difference 
between  the  two  essential  elements  of  the  modern  notion 
of  the  cell — the  anatomic  distinction  between  the  nucleus 
and  the  body  of  the  cell.  The  internal  nucleus  (or 
car  yon)  had  the  appearance  of  a  solid,  definite,  morpho- 
logically distinct  constituent  of  the  cell;  the  outer  and 
softer  mass  which  we  now  call  the  cell-body  {cellctis  or 
cytosoma)  seemed  to  be  a  formless  and  only  chemically 
definable  protoplasm.  It  was  only  discovered  at  a  later 
date  that  the  chemical  composition  of  the  nucleus  is 
closely  akin  to  that  of  the  cell-body,  and  that  we  may 
properly  associate  the  caryoplasm  of  the  one  with  the 
cytoplasm  of  the  other  under  the  general  heading  of 

122 


PLASM 

plasm.  All  the  other  materials  that  we  find  in  the 
living  organism  are  products  or  derivatives  of  the  active 
plasm. 

In  view  of  the  extraordinary  significance  which  we 
must  assign  to  the  plasm — as  the  universal  vehicle  of  all 
the  vital  phenomena  (or  "the  physical  basis  of  life,"  as 
Huxley  said) — it  is  very  important  to  understand  clearly 
all  its  properties,  especially  the  chemical  ones.  This 
is  rendered  somewhat  dilhcult  from  the  circumstance 
that  the  plasm  is,  in  most  of  the  organic  cells,  closely 
bound  up  with  other  substances — the  various  plasma 
products;  it  can  rarely  be  isolated  in  its  purity,  and  can 
never  be  had  pure  in  any  quantity.  Hence  we  are  for 
the  most  part  dependent  on  the  imperfect,  and  often 
ambiguous,  results  of  microscopic  and  microchemical 
research. 

In  every  case  where  we  have  with  great  difficulty 
succeeded  in  examining  the  plasm  as  far  as  possible  and 
separating  it  from  the  plasma-products,  it  has  the  ap- 
pearance of  a  colorless,  viscous  substance,  the  chief 
physical  property  of  which  is  its  peculiar  thickness  and 
consistency.  The  physicist  distinguishes  three  condi- 
tions of  inorganic  matter — solid,  fluid,  and  gaseous. 
Active  living  protoplasm  cannot  strjctly  be  described  as 
either  fluid  or  solid  in  the  physical  sense.  It  presents 
an  intermediate  stage  between  the  two  which  is  best 
described  as  viscous;  it  is  best  compared  to  a  cold  jelly 
or  solution  of  glue.  Just  as  we  find  the  latter  substance 
in  all  stages  between  the  solid  and  the  fluid,  so  we  find 
in  the  case  of  protoplasm.  The  cause  of  this  softness  is 
the  quantity  of  water  contained  in  the  living  matter, 
which  generally  amounts  to  a  half  of  its  volume  and 
weight.  The  water  is  distributed  between  the  plasma 
molecules,  or  the  ultimate  particles  of  living  matter,  in 
much  the  same  way  as  it  is  in  the  crystals  of  salts,  but 
with  the  important  difference  that  it  is  very  variable  in 

J23 


THE    WONDERS    OF    LIFE 

quantity  in  the  plasm.  On  this  depends  the  capacity  for 
absorption  or  imbibition  in  the  plasm,  and  the  mobility 
of  its  molecules,  which  is  very  important  for  the  per- 
formance of  the  vital  actions.  However,  this  capacity 
of  absorption  has  definite  limits  in  each  variety  of 
plasm;  living  plasm  is  not  soluble  in  water,  but  abso- 
lutely resists  the  penetration  of  any  water  beyond  this 
limit. 

The  chemistry  of  living  matter  is  the  most  important 
and  interesting,  but  at  the  same  time  the  most  difficult 
and  obscure,  part  of  the  whole  of  biological  chemistry. 
In  spite  of  the  innumerable  and  careful  investigations 
which  have  been  made  of  it  by  the  ablest  physiologists 
and  chemists  in  the  second  half  of  the  nineteenth 
century,  we  are  still  far  from  a  satisfactory  solution  of 
this  fundamental  problem  of  biology.  This  is  due  partly 
to  the  extraordinary  difficulty  of  isolating  pure  living 
plasm  and  subjecting  it  to  chemical  analysis,  and  partly 
to  the  many  errors  and  misunderstandings  that  have 
arisen  through  one-sided  treatment  of  the  subject,  and 
especially  through  confusion  of  the  chemical  and 
morphological  features  of  plasm.  We  can  thus  under- 
stand the  contradictory  views  that  are  still  put  forward 
by  distinguished  chemists  and  physiologists,  zoologists 
and  botanists.  As  I  cannot  deal  here  with  the  very 
extensive,  elaborate,  and  contradictory  literature  of  the 
subject,  I  must  be  content  to  give  a  brief  summary  of 
the  conclusions  I  have  reached  by  my  reading  and  my 
own  studies  of  plasm  (begun  in  1859). 

To  begin  with,  we  must  clearly  understand  that  proto- 
plasm— in  the  most  general  sense  in  which  we  here  take 
it — is  a  chemical  substance,  not  a  "mixture  of  different 
substances,"  or  a  "mixture  of  a  small  quantity  of  solid 
matter  with  a  good  deal  of  fluid . "  As  Richard  Neumeister 
very  well  observes:  "We  seek  the  nature  of  protoplasm 
in  the  peculiar  processes  which  take  place  in  its  con- 

124 


PLASM 

stituent  matter.  Protoplasm  is  for  us  a  chemical  matter, 
so  pronounced,  in  fact,  that  the  highest  chemical  actions 
that  we  know  of  are  embodied  in  it."  I  must,  from  my 
point  of  view,  entirely  reject  Oscar  Hertwig's  conception 
of  living  matter  as  a  "mixture "  of  a  number  of  chemical 
elements;  because  chemistry  applies  this  phrase  to  vari- 
ous gases  and  powdery  substances  which  are  completely 
indifferent  to  each  other — a  property  which  we  certainly 
do  not  find  in  the  constituents  of  protoplasm.  When  we 
speak  of  the  living  matter  or  protoplasm,  the  general 
phrase  does  not  imply  that  the  substance  may  not  have 
a  distinctive  composition  in  each  particular  case.  And 
when  we  find  many  biologists  still  conceiving  proto- 
plasm as  a  mixture  of  various  substances,  the  error  is 
generally  due  to  a  confusion  of  the  chemical  idea  with 
the  morphological,  and  to  a  belief  that  certain  structural 
features  of  the  plasm  are  primary,  whereas  they  are 
only  secondary,  products  of  the  vital  process  itself  in  the 
cell-body. 

The  older  biologists  who  first  introduced  the  name 
protoplasm  and  studied  it  carefully  recognized  that  this 
living  matter  belonged  to  the  albuminous  (or  proteid) 
group.  The  many  characteristics  which  distinguish 
these  nitrogenous  carbon-compounds  from  all  other 
chemical  compounds — their  behavior  towards  acids  and 
bases,  their  peculiar  color-reaction  towards  certain  salts, 
their  decomposition-products,  etc — are  found  in  all  the 
plasma-substances,  and  in  all  the  other  allmminoids. 
This  is  quite  in  agreement  with  the  results  of  quantita- 
tive analysis.  However  differently  the  various  plasma- 
substances  behave  in  detail,  they  always  exhil)it  the 
same  general  composition  as  the  other  albuminoids  out 
of  the  five  " organogenetic  elements" — namely,  in  point 
of  weight,  fifty -one  to  fifty  -  four  per  cent,  carbon, 
twenty-one  fo  twenty-three  per  cent,  oxygen,  fifteen  to 
seventeen   per  cent,   nitrogen,   six   to   seven   per  cent. 

125 


/  -     V    'f      Iff 

J   -iA        THE    WONDERS    OF    LIFE 

,'l   M  hydrogen,  and  one  to  two  per  cent,  sulphur.     However, 
"  '  '    M   there  is  a  good  deal  of  variety  and  complication  in  the 
^1    j\     way  in  which  the  atoms  of  these  five  elements  are  com- 
^r  bined   in    albumin    and    their   molecules    are    grouped. 

Hence  the  question  of  the  chemical  nature  of  the 
plasma-substances  compels  us  now  to  look  for  a  mo- 
ment at  the  larger  group  of  albuminoids  to  which  they 
belong. 

The  carbon-compounds  which  we  comprise  under  the 
chemical  title  of  the  albumins  or  proteids  are  the  most 
remarkable,  but  also,  unfortunately,  the  least  known, 
of  all  bodies.  The  attempt  to  examine  them  closely 
encounters  extraordinary  difficulties,  greater  than  in  any 
other  group  of  chemical  compounds.  Everybody  is 
familiar  with  the  appearance  of  ordinary  albumm,  from 
the  transparent  viscous  albumin  that  surrounds  the  yolk 
in  the  hen's  egg,  and  which  becomes  a  white,  opaque, 
and  solid  mass  when  it  is  cooked.  However,  this  special 
form  of  albumin,  which  we  can  get  so  easily  in  any 
quantity  from  the  eggs  of  birds  and  reptiles,  is  only  one 
of  the  innumerable  kinds  of  albumin,  or  species  of 
protein,  that  are  to  be  found  in  the  bodies  of  the  various 
animals  and  plants.  Chemists  have  hitherto  tried  in 
vain  to  master  the  chemical  structure  of  these  obscure 
protein-compounds.  They  are  only  rarely  to  be  found 
in  chemically  pure  form  as  crystals.  As  a  rule,  they  are 
in  the  colloid  form,  or  uncrystallized  jelly-like  masses, 
which  offer  a  much  greater  resistance  than  cr3^stals  to 
the  passage  through  a  porous  medium  by  diosmosis  (see 
p.  39).  However,  although  we  have  not  yet  succeeded 
in  penetrating  the  molecular  constitution  of  the  al- 
bumins, the  laborious  research  of  chemists  has  yielded 
some  general  results  which  are  of  great  importance  for 
our  purpose.  We  have,  in  the  first  place,  a  general 
idea  of  their  molecular  constitution. 

Molecules  are  the  smallest  homogeneous  parts  into 

126 


PLASM 

which  a^body  can  be  divided  without  altering  its  chemical 
character.  Hence  the  molecules  of  every  chemical  com- 
pound are  made  up  of  two  or  more  atoms  of  different 
kinds.  The  greater  the  number  of  atoms  in  each  com- 
pound, the  higher  is  its  molecular  weight.  The  space 
between  the  molecules  and  their  component  atoms  is 
filled  with  imponderable  and  highly  elastic  ether.  As 
even  the  largest  molecules  occupy  only  a  very  tiny 
space,  and  remain  far  below  the  range  of  the  most  power- 
ful microscope,  all  our  ideas  of  their  composition  depend 
on  general  physical  theories  and  special  chemical  hy- 
potheses. Nevertheless,  stereochemistry,  the  modern 
science  of  the  molecular  structure  of  chemical  com- 
pounds, is  not  only  a  perfectly  legitimate  section  of  nat- 
ural philosophy,  but  it  yields  the  most  important  con- 
clusions as  to  the  mutual  attractions  of  the  elements 
and  the  invisible  movements  of  the  atoms  in  combining. 
It  further  enables  us  to  calculate  approximately  the 
relative  size  of  the  molecules  and  the  number  of  atoms 
that  are  grouped  together  in  them.  However,  the 
albuminoids  present  the  greatest  difficulty  of  all  in  this 
calculation,  and  their  structural  features  are  still  very 
obscure.  Nevertheless,  science  has  reached  certain 
general  conclusions,  which  we  may  formulate  in  the 
following  propositions: 

1.  The  molecule  of  albumin  is  unusually  large,  and  ( 
therefore  its  molecular  weight  is  very  high  (higher  than 
in  most  or  all  other  compounds). 

2.  The  number  of  atoms  composing  it  is  very  large' 
(probably  much  more  than  a  thousand). 

3.  The  disposition  of  the  atoms  and  groups  of  atoms 
in  the  albuminous  molecule  is  very  complicated,  and  at 
the  same  time  very  unstable — that  is  to  say,  very 
changeable  and  easily  altered. 

These  characters,  which  are  ascribed  to  all  albuminous 
bodies  by  modern  chemistry,  hold  good  of  all  plasma- 

127 


THE    WONDERS    OF    LIFE 

substances;  and,  in  fact,  are  true  in  a  higher  degree  of 
these,  as  the  metaboHsm  of  the  Hving  matter  causes  a 
constant  displacement  of  the  atoms.  This  is  caused, 
according  to  the  view  of  Franz  Hofmeister  and  others, 
by  the  formation  of  ferments  or  enzyma  —  in  other 
words,  by  catalysators  of  a  colloidal  structure.  Verworn 
has,  on  physiological  grounds,  given  the  name  of  biogens 
to  these  plasma-molecules. 

The  profound  insight  which  comparative  anatomy  has 
given  us  into  the  significance  and  nature  of  organs,  and 
comparative  histology  into  those  of  the  cells,  has  nat- 
urally excited  a  desire  to  penetrate  in  the  same  way  the 
mystery  of  the  elementary  structure  of  the  plasm,  the 
chief  active  constituent  of  the  cell.  The  improved  meth- 
ods of  modern  cytology,  and  the  great  progress  which 
this  science  of  the  cell  owes  to  the  microtome  and  to 
microchemistry  with  its  delicate  coloring  processes,  etc., 
have  prompted  many  observers  of  the  last  three  decades 
to  study  the  finest  structural  features  of  the  elementary 
organism,  and  on  this  foundation  build  hypotheses  as  to 
the  elementary  structure  of  protoplasm.  In  my  opinion, 
all  these  theoretical  ideas,  in  so  far  as  they  would  explain 
the  finer  structure  of  pure  plasm,  have  a  very  serious 
defect;  they  relate  to  microscopic  structures  which  do 
not  belong  to  the  plasm  as  such  (as  a  chemical  body), 
but  to  the  cell-body  (or  cytosoma),  the  chief  active 
constituent  of  which  is  certainly  the  plasm.  These 
microscopic  structures  are  not  the  efficient  causes  of  the 
life-process,  but  products  of  it.  They  are  phylogenetic 
outcomes  of  the  manifold  differentiations  which  the 
originally  homogeneous  and  structureless  plasm  has 
undergone  in  the  course  of  many  millions  of  years. 
Hence  I  regard  all  these  "plasma-structures"  (the 
comb,  threads,  granules,  etc.),  not  as  original  and 
primary,  but  as  acquired  and  secondary.  In  so  far  as 
these  structures  affect  the  plasm  as  such,  it  must  take 

128 


P  L  A  S  M 

the  name  of  metaplasm,  or  a  differentiated  plasm, 
modified  by  the  Ufe-process  itself.  The  true  protoplasm, 
or  viscous  and  at  first  chemically  homogeneous  sub- 
stance, cannot,  in  my  opinion,  have  any  anatomic 
structure.  We  shall  see,  when  we  come  to  consider  the 
monera,  that  very  simple  specimens  of  such  organisms 
without  organs  still  actually  exist. 

By  far  the  greater  part  of  the  plasm  that  comes  under 
investigation  as  active  Uving  matter  in  organisms  is 
metaplasm,  or  secondary  plasm,  the  originally  homo- 
geneous substance  of  which  has  acquired  definite 
structures  by  phyletic  differentiations  in  the  course  of 
millions  of  years.  To  this  modified  plasm  we  must 
oppose  the  original  simple  primary  plasm,  from  the 
modification  of  which  it  has  arisen.  The  name  "proto- 
plasm," in  the  narrower  sense,  could  very  properly  be 
retained  for  this  originally  homogeneous  form  of  struct- 
ureless plasm;  but,  as  the  term  has  now  almost  lost 
definite  meaning  and  is  used  in  many  different  senses, 
it  is,  perhaps,  better  to  call  this  pure  homogeneous 
primary  plasm  archiplasm.  It  is  still  found — firstly,  in 
the  body  of  many  (but  not  all)  of  the  monera,  part  of 
the  chromacea  and  bacteria,  and  the  protamoeba  and 
protogenes;  and,  secondly,  in  the  body  of  many  very 
young  protists  and  tissue-cells.  In  the  latter  case,  how- 
ever, there  is  already  a  chemical  differentiation  of  the 
inner  caryoplasm  and  outer  cytoplasm.  When  we 
examine  these  young  cells  under  a  high  power  of  the 
microscope,  with  the  aid  of  the  modern  coloring  meth- 
ods, their  protoplasm  seems  to  be  perfectly  homo- 
geneous and  structureless,  or,  at  the  most,  there  are 
merely  very  fine  granules  regularly  distributed  in  it 
which  are  believed  to  be  products  of  metabolism.  This 
is  best  seen  in  many  of  the  rhizopods,  especially  the 
amoebae,  thalamophora,  and  mycetozoa.  There  are  large 
amoebae,  which  thrust  out  strongly  mobile  feet  from  their 
9  129 


THE    WONDERS    OF    LIFE 

unicellular  body,  broad,  flaplike  processes  of  the  naked 
cell  body  which  constantly  change  their  form,  size,  and 
place.  If  they  are  killed  and  examined  with  the  aid  of 
the  best  methods  of  coloring,  it  is  quite  impossible  to 
detect  any  structure  in  them ;  and  this  is  also  true  of  the 
pseudopodia  of  the  mycetozoa  and  many  other  rhizopods. 
Moreover,  the  slow  flowing  movement  of  the  fluid  proto- 
plasm shows  clearly  that  there  cannot  be  any  composi- 
tion out  of  fine  fixed  elements  in  the  body.  This  is 
particularly  clear  in  those  amoebae  and  mycetozoa  in 
which  a  hyaline,  firm,  and  non-granulated  skin-layer 
(hyaloplasm)  is  more  or  less  separated  from  a  dark, 
softer,  and  granulated  marrow-layer  (polioplasm) ;  as 
both  of  them  are  viscous  and  pass  into  each  other 
without  sharp  limits,  there  cannot  be  any  constant  and 
fixed  structural  features  in  them. 

Organic  life  —  in  its  lowest  and  simplest  form  —  is 
nothing  but  a  form  of  metabolism,  and  therefore  a 
purely  chemical  process.  The  whole  vital  activity  of  the 
chromacea,  the  simplest  and  oldest  organisms  that  we 
know,  is  confined  to  that  process  of  metabolism  which 
we  call  plasmodomism  or  carbon-assimilation.  The 
homogeneous  and  structureless  globules  of  protoplasm, 
which  represent  the  whole  frame  of  these  primitive  pro- 
tophyta  (chroococcus,  aphanocapsa,  etc.)  in  the  simplest 
conceivable  way,  expend  their  whole  vital  power  in  the 
process  of  self -maintenance.  They  maintain  their  indi- 
viduality by  a  simple  metabolism;  they  grow  by  the 
addition  of  fresh  plasm  obtained  by  it,  and  they  split  up 
into  two  equal  globules  of  plasm  when  the  growth  passes 
a  certain  limit — reproduction  by  clevage,  maintenance  of 
the  species.  Thus  these  chromacea  have  neither  special 
organs,  or  organella,  that  we  can  distinguish  in  their 
simple  plasma-bodies,  nor  different  functions  in  their 
life-process;  it  is  wholly  taken  up  with  the  primitive 
work  of  their  vegetal  metabolism.     We  shall  see  later 

130 


PLASM 

on  that  this  is  a  purely  chemical  process,  something  like 
catalysis  in  inorganic  combinations;  and  for  this  neither 
special  organs  nor  fine  elementary  structures  in  the 
plasm  are  needed.  The  "end"  of  their  existence,  self- 
maintenance,  is  attained  just  as  simply  as  in  the  catalysis 
of  any  inorganic  compound,  or  the  formation  of  a  crystal 
in  its  mother-water. 

If  we  compare  this  very  rudimentary  life-process  of 
the  monera  with  that  of  the  highly  differentiated  protists 
(diatomes,  desmidiacea,  radiolaria,  and  infusoria),  the 
biological  distance  between  them  seems  to  be  immense; 
and  it  is,  naturally,  far  greater  when  we  extend  the  com- 
parison to  the  histona,  the  highly  organized  metaphyta 
and  metazoa,  in  the  bodies  of  which  millions  of  cells 
co-operate  in  the  work  of  the  various  tissues  and  organs. 

In  the  great  majority  of  cells — either  the  autonomous 
cells  of  the  protists  or  the  tissue-cells  of  the  histona — 
we  can  detect  more  or  less  definite  and  constant  fine 
structures  in  the  plasm.  We  must  regard  these  always 
as  phyletic,  secondary  products  of  the  life-process,  and 
so  call  the  differentiated  plasm  by  the  name  of  meta- 
plasm.  The  very  different  interpretations  of  the  micro- 
scopic pictures  which  this  metaplasm  affords  have  led  to 
a  good  deal  of  controversy.  In  this  the  desire  to  discover 
in  these  secondary  plasma-structures  the  first  causes  of 
vital  action,  or  the  real  elementary  organella  of  the  cell, 
has  played  a  great  part.  The  most  important  of  the 
theories  that  have  been  formulated  are  those  of  the 
frothy  structure,  the  skeletal  structure,  the  fibrous  struct- 
ure, and  the  granulated  structure  of  the  plasm.  All 
these  theories  of  structure  apply  to  plasm  in  general, 
but  particularly  to  its  two  chief  forms,  thecaryoplasm  of 
the  nucleus  and  the  cytoplasm  of  the  cell-body. 

Among  the  many  different  attempts  to  discover  a 
definite  structure  in  living  matter,  the  theory  of  the 
frothy  structure  (also  called  the  honeycomb  structure) 

131 


THE    WONDERS    OF    LIFE 

has  lately  found  the  most  favor.  Otto  Biitschli,  of 
Heidelberg,  especially,  has  endeavored,  on  the  basis  of 
many  years  of  careful  study  and  experiment,  to  make  it 
the  foundation  of  his  view  of  the  plasm.  It  is  undeniable 
that  the  living  matter  of  many  cells  shows  a  delicate 
structure  which  may  best  be  compared  with  fine  soap- 
suds ;  innumerable  globules  are  crowded  close  together 
in  a  fluid,  and  flatten  each  other  by  their  pressure  into 
polyhedrical  shapes.  In  1892  Butschli  artificially  pro- 
duced fine  oil-suds  by  beating  up  cane  sugar  or  potash 
in  olive  oil,  and  then  put  a  small  drop  of  the  stuff  in  a 
drop  of  water  under  the  microscope.  The  small  particles 
of  sugar  then  exercised  an  attractive  action  by  diffusion 
on  the  particles  of  water;  the  latter  penetrated  into  the 
oily  matter,  released  the  sugar,  and  formed  tiny  vesicles 
with  it.  As  the  vesicles  of  sugar  do  not  mix  with  oil, 
they  look  like  cavities  isolated  on  all  sides,  and  poly- 
hedrically  flattened  by  mutual  pressure.  The  striking 
resemblance  of  this  artificially  produced  "oil  soap-suds" 
to  the  natural  and  microscopically  visible  structures  of 
many  kinds  of  plasm  is  strengthened  from  the  fact  that 
Butschli,  Georg  Quincke,  and  others,  have  also  observed 
similar  flowing  movements  in  both;  and  as  these  ap- 
parently spontaneous  movements  can  be  explained 
physically  and  reduced  to  adhesion,  imbibition,  and 
other  mechanical  causes,  there  seemed  a  prospect  of  re- 
ducing the  "vital"  movements  of  the  living  and  flowing 
plasm  to  purely  physical  forces.  Quite  recently  Ludwig 
Rhumbler,  of  Gottingen,  an  authority  on  the  rhizopods, 
has  endeavored  to  give  in  this  sense  a  Physical  analysis 
of  the  vital  phenomena  in  the  cell.  To-day  the  froth 
theory  is  much  the  most  popular  of  the  many  attempts 
to  detect  a  fine  plasm-structure  as  the  essential  ana- 
tomic foundation  of  an  explanation  of  the  physio- 
logical functions.  It  must  be  noted,  however,  that 
frequently  very  different  phenomena  are  confused  under 

132 


PLASM 

this  name,  especially  the  coarser  froth-formation  by 
taking  up  water  in  the  living  matter  and  the  invisible 
hypothetical  molecular  structure.  Both  these  must  be 
distinguished  from  the  finer  plasma-structure  which  is 
visible  under  a  powerful  microscope;  but  the  limit  be- 
tween them  is  difficult  to  determine. 

A  second  view  of  the  finer  structure  of  the  plasm, 
which  had  been  greatly  esteemed  before  the  acceptance 
of  the  froth  theory,  was  formulated  in  1875  by  Carl 
Frommann  and  Carl  Heitzmann,  and  supported  by 
Leydig,  Schwitz,  and  others.  It  puts  another  interpre- 
tation on  the  net-like  appearance  of  the  microscopic 
plasma-structure.  It  assumes  that  the  plasma  consists 
of  a  skeleton  of  fine  threads  or  fibrils  combined  in 
the  form  of  a  net,  and  that  these  spread  and  cross  in  the 
body  of  the  cell  which  is  filled  with  fluid.  It  is  also 
compared  to  a  sponge,  and  is  said  to  have  a  spongy 
structure.  We  can  artificially  produce  such  a  skeletal 
structure  by,  for  instance,  causing  coagulation  in  a  thick 
solution  of  glue  or  albumin  by  adding  alcohol  or  chromic 
acid.  It  is  unquestionable  that  there  are  these  "plasma- 
skeletons"  both  in  the  nucleus  and  the  body  of  the  cell; 
but  they  are  generally  (if  not  always)  secondary  prod- 
ucts of  organization  in  the  elementary  organism  (or 
cell  -  organs),  not  primitive  structures  of  its  plasm. 
Moreover,  an  optical  transverse  action  of  a  froth- 
structure  or  honeycomb,  examined  as  a  flat  surface  in 
the  microscope,  shows  the  same  configuration  as  a  fine 
skeleton.  We  can  hardly  see  any  difference  between  the 
two.  We  cannot  accept  the  skeletal  formation  as  a 
fundamental  structure  of  the  plasm. 

As  we  notice  very  fine  threads  in  the  plasm  of  many 
cells,  both  in  the  caryoplasm  of  the  nucleus  and  the 
cytoplasm  of  the  cell  body,  the  cytologist  Flemming,  of 
Kiel  (1882),  believed  it  was  possible  to  discover  them  in 
the  plasm  of  all  cells,  and  based  on  this  his  filar  theory 

^33 


THE    WONDERS    OF    LIFE 

of  plasm.  He  says  that  we  must  distinguish  two  chemi- 
cally different  kinds  of  plasm  in  living  matter — the^ filar 
(threadlike)  and  the  inter-filar  matter.  The  fine  threads 
of  the  former  are  of  different  lengths,  and  sometimes 
run  separately,  at  other  times  are  bound  in  a  sort 
of  net-work  {mitoma  and  paramitomd).  In  certain 
conditions  of  cell-life,  especially  in  indirect  cell-division, 
these  filar  formations  play  a  great  part;  and  also  in  the 
functions  of  highly  differentiated  cells,  such  as  the 
ganglionic  cells.  But  in  many  cases  these  plasma 
threads  may  be  merely  parts  of  a  skeletal  or  frothy 
structure  (honeycomb  walls  in  section).  In  any  case, 
we  cannot  regard  the  thread  formation  as  a  general 
elementary  structure  of  plasm;  in  my  opinion,  it  is 
always  a  secondary  phyletic  product  of  living  matter, 
and  never  a  primary  feature  of  it. 

Totally  different  from  the  three  preceding  theories  of 
the  finer  structure  of  the  plasm  is  the  granular  theory  of 
Altmann  (1890).  He  supposes  that  all  living  matter  is 
originally  made  up  of  tiny  round  granules,  and  that  these 
independently  living  hiohlgsts  are  the  real  "elementary 
organisms,"  the  microscopic  ultimate  individuals;  hence 
the  cells  which  are  formed  by  the  combination  of 
these  granules  must  be  looked  on  as  individuals  of  the 
second  order.  Between  the  granules  of  the  granulated 
substance  (the  real  active  living  matter)  there  is  always 
an  inter-granular  substance;  the  granules  are  regularly 
distributed  and  arranged  in  these.  The  granules  them- 
selves, or  the  bioblasts,  are  homogeneous,  sometimes 
globular,  and  sometimes  oval,  or  of  other  shapes. 
However,  the  distinction  between  these  substances  is 
quite  arbitrary,  and  neither  chemically  nor  morphologi- 
cally well  defined.  Under  the  head  of  granules  Altmann 
throws  together  the  most  different  contents  of  the  cell — 
fat  granules,  pigment  granules,  secretory  granules,  and 
other    products    of    metabolism.     Hence    his    granular 

134 


PLASM 

theory  is  now  generally  rejected.  However,  there  was  a 
sound  idea  at  the  bottom  of  it — namely,  the  idea  of 
explaining  the  vital  properties  and  functions  of  living 
matter  by  small  separate  constituents  which  make  up 
the  plasm,  and  move  in  a  viscous  medium.  But  these 
real  elementary  parts  are  not  microscopically  visible; 
they  belong  to  the  molecular  world,  which  lies  far  below 
the  limit  of  microscopic  power.  In  my  opinion,  Alt- 
mann's  visible  granules,  like  Flemming's  threads  and 
Frommann's  skeleton  and  Biitschli's  honeycomb,  are  not 
primary  structures,  but  secondary  products  of  plasma 
differentiation. 

As  the  special  properties  and  activities  of  any  natural 
body  depend  on  its  chemical  constitution,  and  this  is,  in 
the  long-run,  determined  by  the  composition  of  its 
molecules,  it  is  a  matter  of  the  greatest  interest  in 
biology  to  form  as  clear  and  distinct  an  idea  as  possible 
of  the  nature  and  properties  of  the  molecules  of  plasm. 
Unfortunately,  it  is  only  possible  to  do  this  approximate- 
ly, and  to  a  slight  extent.  As  the  hypotheses  of  modem 
structural  chemistry  on  the  molecular  formation  of  com- 
plicated organic  compounds  are  often  very  unsafe,  this  is 
bound  to  be  the  case  in  the  highest  degree  as  regards  the 
albuminoids  and,  the  most  important  of  all,  the  living 
matter  or  plasm.  We  have  as  yet  no  knowledge  of  the 
fundamental  features  of  its  very  variable  chemical 
structure.  The  one  thing  that  bio-chemists  have  told 
us  about  it  is  that  the  molecule  of  plasm  is  very  large,  and 
made  up  of  a  great  number  of  atoms  (over  a  thousand) ; 
and  that  these  are  combined  in  smaller  or  larger  groups, 
and  are  in  a  state  of  very  unstable  equilibrium,  so  that 
the  life  process  itself  causes  constant  changes  in  them. 

Since  the  great  problem  of  heredity  was  forced  by 
Darwin  in  1859  into  the  foreground  of  general  biology, 
manv  different  hypotheses  and  theories  of  it  have  been 
framed.   All  these  have  in  the  end  to  trace  it  to  molecular 

135 


THE    WONDERS    OF    LIFE 

features  in  the  plasm  of  the  germ-cells;  because  it  is 
this  germ-plasm  of  the  maternal  ovum  and  the  paternal 
sperm  -  cell  that  conveys  the  characteristics  of  the 
parents  to  the  child.  Hence  the  great  progress  that  has 
been  made  recently  in  the  study  of  conception  and 
heredity,  by  means  of  a  number  of  remarkable  observa- 
tions and  experiments,  has  been  of  service  to  our  ideas 
on  the  molecular  structure  of  the  plasm.  I  have  dealt 
with  the  chief  of  these  theories  in  the  ninth  chapter  of 
my  History  of  Creation y  and  must  refer  the  reader  thereto. 
In  chronological  order  we  have:  (i)  the  pangenesis 
theory  of  Darwin  (1868),  (2)  the  perigenesis  theory  of 
Haeckel(i875),  (3)  the  idioplasm  theory  of  NageH  (1884), 
(4)  the  germ -plasm  theory  of  Weismann  (1885),  and  (5) 
the  mutation-theory  of  De  Bries  (1889).  None  of  these 
attempts,  and  none  of  the  later  theories  of  heredity,  has 
given  us  a  satisfactory  and  generally  admitted  idea  of 
the  plasma-structure.  We  are  not  even  clear  as  to 
whether  in  the  last  resort  life  is  to  be  traced  to  the 
several  molecules,  or  to  groups  of  molecules,  in  the 
plasm.  With  an  eye  to  this  latter  difference,  we  may 
distinguish  the  plastidule  and  micellar  theories  as  two 
different  groups  of  relevant  hypotheses. 

In  my  essay  on  "The  Perigenesis  of  the  Plastidules" 
(1875)  I  formulated  the  hypothesis  that  in  the  last 
instance  the  plastidules  are  the  vehicles  of  heredity — 
that  is  to  say,  plasma-molecules  which  have  the  property 
of  memory.  In  this  I  found  support  in  the  ingenious 
theory  of  the  distinguished  physiologist,  Ewald  Hering, 
who  had  declared  in  1870  that  "memory  is  a  general 
property  of  organic  matter."  I  do  not  see  still  how 
heredity  can  be  explained  without  this  assumption !  The 
very  word  "reproduction,"  which  is  common  to  both 
processes,  expresses  the  common  character  of  psychic 
memory  (as  a  function  of  the  brain).  By  plastidules  I 
understand  simple  molecules;  the  homogeneous  nature 

136 


PLASM 

of  the  plasm  in  the  monera  (both  chromacea  and  bacteria 
and  rhizomonera)  and  the  primitive  simplicity  of  their 
life-functions  do  not  dispose  us  to  think  that  special 
groups  of  molecules  are  to  be  distinguished  in  these  cases. 
Max  Verworn  has  recently  (1903)  formulated  his  biogen- 
hypothesis  in  the  same  sense,  as  a  "critical-experimental 
study  of  the  processes  in  the  living  matter."  He  also 
takes  the  active  plasma-molecules,  which  he  calls  biogens, 
as  the  ultimate  individual  factors  of  the  life-process,  and 
is  convinced  that  in  the  simplest  cases  the  plasm  consists 
of  homogeneous  biogen-molecules. 

The  hypothesis  of  Nageli  (1884)  and  Weismann  (1885) 
is  totally  difi[erent  from  the  hypothesis  of  the  plastidules 
and  biogens  as  simple  molecules  of  the  plasm.  Accord- 
ing to  this,  the  ultimate  "vital  unities"  or  individual 
vehicles  of  the  life-process  are  not  homogeneous  plasma- 
molecules,  but  groups  of  molecules,  made  up  of  a 
number  of  dififerent  molecules.  Nageli  calls  them 
micella,  and  assigns  them  a  crystalline  structure.  He 
supposes  that  these  micella  are  combined  chainwise  into 
micellar  ropes,  and  that  the  variety  of  the  many  forms 
and  functions  of  plasm  is  due  to  the  different  configura- 
tion and  arrangement  of  these.  Weismann  says:  "Life 
can  only  arise  by  a  definite  combination  of  different 
kinds  of  molecules,  and  all  living  matter  must  be  made 
up  of  these  groups  of  molecules.  A  single  molecule 
cannot  live,  can  neither  assimilate  nor  grow  nor  repro- 
duce." I  do  not  see  the  justice  of  this  observation. 
All  the  chemical  and  physiological  properties  which 
Weismann  afterwards  attributes  to  his  hypothetical 
hiophora  may  be  ascribed  to  a  single  molecule  just  as 
well  as  to  a  group  of  molecules.  In  the  simplest  forms 
of  the  monera  (both  the  chromacea  and  the  bacteria)  the 
nature  of  their  rudimentary  life  can  be  explained  on  the 
one  supposition  just  as  well  as  the  other.  Naturally, 
this    does   not   exclude    a    very    complicated    chemical 

137 


THE    WONDERS    OF    LIFE 

structure  in  the  large  plastidule  or  biogen  as  a  single 
molecule.  Verworn's  biogen-hypothesis  seems  to  me 
quite  satisfactory  when  it  represents  the  primitive 
molecule  of  living  matter  as  really  the  ultimate  factor 
of  life. 

The  chief  process  in  the  evolutionary  history  of  the 
plasm  is  its  separation  into  the  inner  nuclear  matter 
(caryoplasm)  and  the  outer  cellular  matter  (cytoplasm). 
When  both  kinds  of  plasm  arose  by  differentiation  from 
the  originally  simple  plasm  of  the  monera,  there  also 
took  place  the  morphological  separation  of  the  nucleus 
(caryon)  and  cell-body  (cytosoma  or  celleus).  As  these 
two  chief  forms  of  living  matter  are  chemically  different 
but  nearly  related,  and  as  they  may  in  certain  circum- 
stances (for  instance,  during  indirect  cell-division  and 
the  partial  caryolysis  connected  therewith)  enter  into  the 
closest  mutual  relations,  we  must  suppose  that  the 
original  severance  of  the  two  substances  took  place 
gradually  and  during  a  long  period  of  time.  It  was  not 
by  a  sudden  bound  or  transformation,  but  by  a  gradual 
and  progressive  formation  of  the  chemical  antithesis  of 
caryoplasm  and  cytoplasm,  that  the  real  nucleated  cell 
(cytos)  arose  from  the  unnucleated  cytode  (or  primitive 
cell).  Both  may  correctly  be  comprised  under  the 
general  head  of  plastids  (or  formative  principles),  as 
"ultimate  individualities." 

I  regard  as  the  chief  cause  of  this  important  differen- 
tiation of  the  plasm  the  accumulation  of  hereditary 
matter — that  is  to  say,  of  the  internal  characteristics 
of  the  plastids  acquired  by  ancestors  and  transmitted 
to  their  descendants — within  the  plastids  while  their 
outer  portion  continued  to  maintain  the  intercourse 
with  the  outer  world.  In  this  way  the  inner  nucleus 
became  the  organ  of  heredity  and  reproduction,  and 
the  outer  cell-body  the  organ  of  adaptation  and  nutri- 
tion.    I   put  forward   this   hypothesis   in    1866   in   my 

138 


PLASM 

General  Morplioloi^y:  "The  two  functions  of  heredity 
and  adaptation  seem  to  be  not  yet  distributed  between 
differentiated  substances  in  the  unnucleated  cytodes, 
but  to  inhere  in  the  whole  of  the  homogeneous  mass 
of  the  plasm;  while  in  the  nucleated  cell  they  are  di- 
vided between  the  two  active  constituents  of  the  cell, 
the  inner  nucleus  taking  over  the  transmission  of  hered- 
itary characters  and  the  outer  plasm  undertaking 
adaptation,  or  the  accommodation  to  the  features  of  the 
environment."  This  hypothesis  was  afterwards  (1873) 
confirmed  by  the  discoveries  of  Strasburger,  the  brothers 
Hertwig,  and  others,  with  regard  to  cell-cleavage  and 
fertilization ;  it  is  particularly  supported  by  the  phenom- 
ena of  caryokinesis  (the  movement  of  the  nucleus)  in 
sexual  generation.  Hence  we  can  understand  how  it  is 
that  in  the  monera  (chromacea  and  bacteria),  which 
propagate  by  simple  cleavage,  there  is  no  sexual  genera- 
tion and  no  nucleus. 

The  great  significance  of  the  nucleus  in  the  life  of  the 
cell,  as  central  organ  of  heredity,  and  also  probably  as 
"the  soul  of  the  cell,"  depends  chiefly  on  the  chemical 
properties  of  its  albuminous  matter,  the  caryoplasm. 
This  one  indispensable  nuclear  element  is  chemically 
akin  to  the  cytoplasm  of  the  cell-body,  but  differs  from  it 
in  certain  respects.  The  caryoplasm  has  a  greater 
affinity  for  many  coloring  matters  (carmine,  haematoxy- 
lin,  etc.)  than  the  cytoplasm;  and  the  former  coagulates 
more  quickly  and  firmly  than  the  latter  through  acids 
(such  as  acetic  and  chromic  acid).  Hence  we  need  only 
add  a  drop  of  diluted  (two  per  cent.)  acetic  acid  to  cells 
that  seem  homogeneous  to  make  perfectly  clear  the 
separation  between  the  inner  nucleus  and  outer  body. 
As  a  rule,  the  firmer  nucleus  then  stands  out  sharply  as  a 
globular  or  oval  particle  of  plasm;  occasionally  it  has 
other  forms  (cylindrical,  conical,  spiral,  or  branched). 
The  caryoplasm  seems  to  be  originally  quite  homogene- 

139 


THE    WONDERS    OF    LIFE 

ous  and  structureless,  as  we  find  in  many  of  the  protists 
and  many  young  cells  of  histona  (especially  young 
embryos).  But  in  the  great  majority  of  cells  the  caryo- 
plasm  is  divided  into  two  or  more  different  substances, 
the  chief  of  them  being  chromatin  and  achromin. 

The  most  common  division  of  the  caryoplasm  in  the 
cells  of  the  animal  and  plant  body,  and  the  one  of  chief 
significance  for  their  vital  activity,  is  that  into  two 
chemically  different  substances,  which  are  usually  called 
chromatin  (or  nuclein)  and  achromin  (or  linin).  Chro- 
matin has  a  greater  affinity  for  coloring  (chromos) 
matter  (carmine,  haematoxylin,  etc.),  and  so  this 
"colorable  nuclear  matter"  is  particularly  regarded 
as  the  vehicle  of  heredity.  The  achromin  (or  achro- 
matin,  or  linin)  is  either  not  at  all  or  less  easily  color- 
able, and  is  akin  to  the  cytoplasm;  in  direct  cell-division 
it  enters  into  close  relations  with  the  latter.  Achromin 
is  usually  found  in  the  form  of  slender  threads,  and 
hence  called  "nuclear  thread-matter"  (linin).  Chro- 
matin is  generally  found  in  roundish  or  rod-shaped 
granules  (chromosomata),  which  exhibit  very  charac- 
teristic changes  of  form  (loop  formation,  etc.)  in  indirect 
cell-division.  The  chemical,  physiological,  and  morpho- 
logical difference  between  chromatin  and  achromin  must 
not  be  regarded  as  an  original  property  of  cell  nuclei  (as 
is  wrongly  stated  sometimes),  but  is  the  outcome  of  a 
very  early  phylogenetic  differentiation  in  the  originally 
homogeneous  caryoplasm;  and  this  holds  also  of  two 
other  parts  of  the  nucleus  —  the  nucleolus  and  cen- 
trosoma. 

In  a  good  many  cells,  but  by  no  means  universally, 
we  find  two  other  constituents  of  the  nucleus,  which  owe 
their  rise  to  a  further  differentiation  of  the  caryoplasm. 
The  nucleolus  is  a  small  globular  or  oval  particle,  which 
may  be  found  singly  or  in  numbers  in  the  nucleus,  and 
behaves  somewhat  differently  towards  coloring  matter 

140 


P  L  A  S  M 

than  the  closely  related  chromatin.  It  has  a  special 
aflinity  for  acid  aniline  colors,  gosin,  etc.  Its  substance 
has,  therefore,  been  distinguished  as  plastin  or  para- 
nnclcin.  The  nucleolus  is  especially  found  in  the  tissue- 
cells  of  the  higher  animals  and  plants  as  an  independent 
constituent;  it  is  wanting  in  many  of  the  unicellular 
protists.  The  same  may  be  said  of  the  centrosoma,  or 
"central  body"  of  the  cell.  This  is  an  extremely  small 
granule,  on  the  very  limit  of  visibility,  the  chemical  com- 
position of  which  is  not  known  very  well.  We  should 
have  paid  no  attention  to  this  constituent  of  the  cell 
(distinguished  in  1876)  if  it  did  not  play  an  important, 
and  perhaps  leading,  part  in  indirect  cell-division.  As 
the  "polar  body  in  the  division  of  the  nucleus,"  the 
centrosoma  exercises  a  peculiar  attraction  on  the 
granules  distributed  in  the  cytoplasm,  which  arrange 
themselves  radially  about  this  centre.  The  centrosomata 
grow  independently  and  increase  by  cleavage,  like  the 
chromoplasts  (chlorophyll  particles,  etc.).  When  they 
have  split  up,  each  of  the  daughter-microsomata  acts  in 
turn  as  a  centre  of  attraction  on  its  half  of  the  cell. 
However,  the  great  importance  which  modern  cytologists 
have  ascribed  to  it  on  this  account  is  discounted  by 
two  circumstances.  In  the  first  place,  we  have  not 
succeeded,  in  spite  of  all  efforts,  in  discovering  a  centro- 
soma in  the  cells  of  the  higher  plants  and  many  of  the 
protists;  and,  in  the  second  place,  a  number  of  recent 
chemical  experiments  have  succeeded  in  producing 
centrosomata  artificially  (for  instance,  by  the  addition  of 
magnesium  chloride)  in  the  cytoplasm.  Hence  many 
cytologists  regard  the  centrosoma  as  a  secondary  product 
of  differentiation  in  the  cell-body,  not  the  nucleus. 

Two  other  parts  of  the  nucleus  that  we  find  very  often, 
but  by  no  means  universally,  in  the  cells  of  the  animal 
and  plant  body  are  the  nuclear  membrane  (caryotheca) 
and  the  nuclear  sap  (caryolymph).     A  large  number  of 

141 


THE    WONDERS    OF    LIFE 

cells — but  not  all — have  the  appearance  of  vesicles, 
having  a  thin  skin  enclosing  a  liquid  content,  the  nuclear 
sap.  The  achromin  then  usually  forms  a  frame-work  of 
threads,  with  chromatin  granules  in  its  meshes  or 
knots,  within  this  round  vesicle.  This  very  thin  nuclear 
membrane  (often  only  visible  as  its  contour)  or  cary- 
otheca  may  be  regarded  as  the  result  of  surface-strain 
(at  the  planes  of  contact  of  caryoplasm  and  cytoplasm). 
The  watery  and  usually  clear  and  transparent  nuclear 
sap  (caryolymph)  is  formed  by  imbibition  of  watery 
fluid  (like  the  frothy  structure  of  the  plasm  in  general). 
The  separation  of  the  nuclear  membrane  and  nuclear 
sap  is  not  a  primary  property  of  the  nucleus,  but  is  due 
to  a  secondary  differentiation  in  the  originally  homo- 
geneous caryoplasm. 

Like  the  caryoplasm  of  the  nucleus,  the  cytoplasm  of 
the  cell-body  is  originally  a  chemical  modification  of  the 
simple  and  once  homogeneous  plasm  (the  archiplasm). 
This  is  clearly  shown  by  the  comparative  biology  of  the 
protists,  their  unicellular  organism  presenting  a  much 
greater  variety  of  stages  of  cell-organization  than  the 
subordinate  tissue-cells  in  the  bodies  of  the  multicellular 
histona.  However,  in  the  great  majority  of  cells  the 
cytoplasm  is  separated  into  several,  and  frequently  very 
numerous,  parts,  which  have  received  diverse  forms  and 
functions  in  the  division  of  labor.  We  then  see  very 
conspicuously  the  regularity  of  cell-organization,  which 
is  altogether  wanting  in  the  simple  homogeneous  plasma 
granules  of  the  monera.  As  this  great  differentiation 
of  the  advanced  elementary  organism  is  incorrectly 
generalized  by  some  recent  cytologists  and  described 
as  a  universal  feature  of  cells,  it  is  necessary  to  insist 
explicitly  that  it  is  a  secondary  phylogenetic  develop- 
ment, and  is  altogether  wanting  in  the  primitive  or- 
ganisms. The  complexity  of  the  physiological  division 
of  labor  and  the  accompanying  morphological  separation 

142 


PLASM 

of  parts  is  extremely  great  in  the  cytoplasm.  When  we 
wish  to  arrange  them  in  a  few  large  groups  from  a 
general  point  of  view,  we  may  distinguish  the  active 
plasma-formations  from  the  passive  plasma-products; 
the  former  are  due  to  a  chemical  metamorphosis  of  the 
living  plasm,  the  latter  lifeless  excretions  from  it. 

Under  the  head  of  plasm-formations,  or  products  of 
differentiation  in  the  cytoplasm,  we  comprise  all  forma- 
tions that  are  due  to  partial  metamorphosis  of  the  living 
cell-body — not  lifeless  excretions  from  it,  but  living  parts 
of  its  substance,  undertaking  special  functions,  and 
therefore  chemically  and  morphologically  differentiated 
from  the  primary  cytoplasm.  One  of  the  commonest  dif- 
ferentiations of  this  kind  is  the  separation  of  the  firm 
hyaline  skin-layer  (hyaloplasm)  from  the  softer  granular 
marrow-layer  (polioplasm) ;  though  the  two  often  pass 
into  each  other  without  clear  limits.  In  most  plant-cells 
special  granules  of  plasm,  mostly  globular  or  roundish, 
are  developed,  called  tropJioplasts,  and  these  undertake 
the  work  of  metabolism.  To  this  class  belong  the  amylo- 
plasts,  which  produce  starch  (amylum),  the  chloroplasts 
or  chlorophyll-granules  which  form  the  green  matter 
(chlorophyll)  in  the  leaf,  and  the  chromoplasts  which 
form  color-crystals  of  various  sorts.  In  the  cells  of  the 
higher  animals  the  myoplasts  form  the  special  contractile 
tissue  of  the  muscles,  and  the  neuroplasts  the  psychic 
tissue  of  the  nerve-matter.  On  the  other  hand,  the  dis- 
tinction between  the  body-plasm  (somoplasma)  and  the 
germ-plasm  (germoplasma),  which  serves  as  the  base  of 
Weismann's  untenable  theory  of  the  germ-plasm  (cj. 
chapter  xvi.),  is  purely  hypothetical  and  without  direct 
observation  to  support  it. 

The  infinite  variety  of  parts  of  the  cell  which  arise  as 
excretions  of  the  living  active  cytoplasm,  and  so  must  be 
regarded  as  lifeless  plasma-products,  may  be  divided  into 
two  chief  groups — internal  and  external.     The  former 

143 


THE    WONDERS    OF    LIFE 

are  stored  within  the  living  cytoplasm,  the  latter  thrust 
out  from  it. 

Internal  plasma-products  of  common  occurrence  are 
the  microsomata,  very  small  and  opaque  particles  which 
are  generally  regarded  as  products  of  metabolism.  They 
consist  sometimes  of  fat,  sometimes  of  derivatives  of 
albumin,  sometimes  of  other  substances  of  which  we  do 
not  know  the  chemical  composition.  The  same  may  be 
said  of  the  large  and  variously-colored  pigment-granules, 
which  are  very  common  and  determine  the  color  of 
tissues.  Also  very  common  in  the  cytoplasm  are  large 
accumulations  of  fat  in  the  shape  of  oil-globules,  fat- 
crystals,  etc.,  besides  other  crystals  of  a  very  different 
sort,  partly  organic  crystals  (for  instance,  albuminous 
crystals  in  the  aleuron  -  granules  of  plants),  partly 
inorganic  crystals  (for  instance,  of  oxalic-acid  salts  in 
many  plant-cells,  of  calcareous  salts  in  many  animal- 
cells).  The  watery  cell-sap  (cytolymph)  plays  an  impor- 
tant part  in  many  of  the  larger  cells.  It  is  formed  by  the 
accumulation  of  fluid  in  the  cytoplasm,  and  is  found  in 
its  frothy  structure.  The  large  empty  spaces  which  it 
forms  are  called  vacuoles,  with  very  regularly  disposed 
alveoles.  When  the  cell-sap  gathers  in  great  abundance 
within  the  cell,  we  get  the  large  vesicular  cells  which 
are  found  in  the  tissues  of  the  higher  plants,  the  carti- 
lages, etc. 

As  external  excretions  of  the  living  cytoplasm  that 
have  acquired  some  importance,  especially  as  protective 
organs,  in  the  majority  of  cells,  we  have  first  of  all  the 
cell -membranes,  the  firm  capsules  or  protective  skins 
which  enclose  the  soft  cell-body,  like  a  snail  in  its  house. 
In  the  first  period  of  the  cell-theory  (i 838-1 859)  such  an 
integument  was  ascribed  to  all  cells,  and  often  regarded 
as  their  chief  constituent;  but  it  was  discovered  after- 
wards that  this  protective  skin  is  altogether  wanting  in 
many  (especially  animal)  cells,  and  that  it  is  not  found 

144 


PLASM 

in  many  when  they  are  young,  but  grows  subsequently. 
We  now  distinguish  between  naked  cells  (gymnocytes) 
and  covered  cells  (thecocytes).  As  examples  of  naked 
cells  we  have  the  amoebae,  and  many  of  the  infusoria, 
the  spores  of  algae,  the  spermatozoa,  and  many  animal 
tissue-cells. 

The  cell-covering  (cytotheca)  varies  very  much  in  size, 
shape,  composition,  and  chemical  character,  especially 
in  the  rhizopods  among  the  unicellular  protists.  The 
tlint  shells  of  the  radiolaria  and  diatomes,  the  chalky 
cells  of  the  thalamophora  and  calcocytea,  the  cellulose 
shells  of  the  desmidiacea  and  syphonea,  show  the  ex- 
traordinary plasticity  of  the  constructive  cytoplasm  {cf. 
chapter  viii.).  Among  the  histona  the  tissue-plants  are 
remarkable  for  the  infinite  variety  of  shape  and  differ- 
entiation of  their  cellulose  capsules.  The  familiar  prop- 
erties of  wood,  cork,  bast,  the  hard  shells  of  fruit,  etc., 
are  due  to  the  manifold  chemical  modification  and  mor- 
phological differentiation  which  the  cellulose  membrane 
undergoes  in  the  tissues  of  plants.  This  is  less  fre- 
quently seen  in  the  tissues  of  animals;  but,  on  the  other 
hand,  the  intercellular  and  the  cuticular  matter  play  a 
greater  part  in  these. 

The  intercellular  matter,  an  important  external 
plasma-product,  is  formed  by  the  social  cells  in  the 
tissues  of  the  histona  thrusting  out  in  common  firm 
protective  membranes.  These  protective  structures  are 
very  common  among  communities  of  protists,  in  the 
form  of  masses  of  jelly,  in  which  a  number  of  cells  of 
the  same  kind  are  united ;  such  are  the  zoogloea  of  many 
of  the  bacteria  and  chromacea,  the  common  jelly-like 
envelope  of  the  volvocina  and  many  diatomes,  and  the 
globular  cell-communities  of  the  polycyttaria  (or  social 
radiolaria).  The  chief  part  is  played  by  intercellular 
matter  in  the  body  of  the  higher  animals,  in  the  form  of 
mesenchyma-tissue ;   the   connecting   tissue,    cartilages, 

lo  145 


THE    WONDERS    OF    LIFE 

and  bones  owe  their  peculiar  property  to  the  amount 
and  quality  of  the  intercellular  matter  that  is  deposited 
between  the  social  cells. 

When  the  socially  joined  epidermic  cells  at  the  surface 
of  the  tissue-bod}"  thrust  forth  in  common  a  protective 
covering,  we  get  the  cuticles,  which  are  often  thick  and 
solid  armor-plates.  In  many  of  the  metaphyta  wax 
and  flinty  matter  are  deposited  in  the  cellulose  cuticles. 
The  strongest  formation  is  found  in  the  invertebrate 
animals,  where  the  cuticle  often  determines  the  whole 
shape  and  articulation,  as  in  the  calcareous  shells  of 
mollusks  (mussel-shells,  snail-shells,  cockle-shells,  etc.); 
and  especially  the  coats  of  the  articulata  (the  crab's 
coat  of  mail,  and  the  skins  of  spiders  and  insects). 


VII 
UNITIES  OF  LIFE 

Units  of  life — Simple  and  complex  organisms — Morphological 
and  physiological  individuals — Morphonta  and  bionta — 
Stages  of  individuality:  cell,  person,  stem — Actual  and 
virtual  bionta — Partial  and  genealogical  bionta — Meta- 
physical individuals  —  Cells  (elementary  organisms) — Cell 
membranes  —  Unnucleated  cells  —  Plastids  (cytodes  and 
cells) — Primitive  cells  and  nucleated  cells — Organella  (cell 
organs) — Cell  communities  (coenobia) — Tissues  of  histona 
— Systems  of  organs — Organic  apparatus — Histonal  indi- 
viduals (sprouts  and  persons) — Articulation  of  the  histona 
(metamerism) — Stems  of  the  histona — Animal  states. 

THE  dissection  of  the  body  of  the  higher  animal  and 
plant  into  its  various  organs  soon  prompted  com- 
parative anatomists  to  draw  a  distinction  between  sim- 
ple and  complex  organisms.  Then,  when  the  cell-the- 
ory developed  in  the  course  of  the  last  half -century, 
the  common  anatomic  groundwork  of  all  living  forms 
was  recognized  in  the  cell;  and  the  conception  of  the 
cell  as  the  elementary  organism  led  to  the  further  belief 
that  our  own  frame,  like  that  of  all  the  higher  animals 
and  plants,  is  a  cell-state,  composed  of  millions  of  micro- 
scopic citizens,  the  individual  cells,  which  work  more  or 
less  independently  therein,  and  co-operate  for  the  com- 
mon purposes  of  the  entire  community.  This  funda- 
mental principle  of  the  modern  cell-theory  was  applied 
with  great  success  by  Rudolph  Virchow  to  the  diseased 
organism,  and  led  to  most  important  reforms  in  medi- 
cine.    The  cells  are,  in  his  view,  independent  "life-uni- 

U7 


THE    WONDERS    OF    LIFE 

ties  or  individual  life-centres,"  and  the  unified  life  of 
the  whole  man  is  the  combined  result  of  the  work  of  his 
component  cells.  In  this  way  the  c^ls  are  the  real  life- 
unities  of  the  organism.  Their  individual  independence 
is  at  once  seen  in  the  permanently  unicellular  protists, 
of  which  several  thousand  species  are  already  known 
to  us. 

On  the  other  hand,  we  find  among  the  lower  animals 
and  the  higher  plants  a  composition  of  homogeneous 
parts,  which  represents  a  higher  stage  of  life-unity. 
The  tree  is  an  individual,  but  it  is  made  up  of  a  number 
of  branches  or  individual  sprouts,  each  of  which  consists 
in  like  manner  of  an  axial  stem  with  leaves  attached. 
If  we  detach  such  a  branch  and  plant  it  in  the  ground, 
it  takes  root  and  grows  into  an  independent  plant.  So 
the  coral-stem  is  made  up  of  a  number  of  individual 
animals  or  persons,  each  of  which  has  its  own  stomach 
and  mouth  with  a  crown  of  tentacles.  Each  several 
coral-individual  is  equivalent  to  a  single  living  polyp 
(actinia).  Thus  the  stem  (cormus)  is  a  higher  unity, 
both  in  the  animal  and  the  plant  world.  Even  the  herds 
of  gregarious  animals,  the  swarms  of  bees  and  ants,  and 
the  communities  of  human  beings,  are  similar  unities; 
with  the  difference  that  the  individual  persons  or  citizens 
are  not  physically  connected,  but  held  together  by  com- 
mon interests.  We  can,  therefore,  distinguish  three 
stages  of  organic  individuality,  one  building  upon  the 
other — the  cell,  the  person  (or  sprout),  and  the  stejn  or 
state  (cormus).  Each  higher  unity  represents  an  inti- 
mate union  of  lower  individuals.  Morphologically,  in 
relation  to  their  anatomic  structure,  the  latter  are  in- 
dependent; but  physiologically,  in  respect  of  the  life- 
unity  of  the  whole,  they  are  subordinated  to  the  former. 
—  This  relation  is  quite  clear  in  the  familiar  examples  I 
have  quoted.  But  there  are  other  organisms  in  which 
this  is  not  so,  and  where  the  question  of  the  real  individ- 

148 


UNITIES    OF    LIFE 

uality  is  very  difficult  to  answer.  Thus,  fifty  years  ago, 
we  came  to  recognize  floating  animal-stems  in  the  re- 
markable siphonophora,  or  social  medusc'c,  which  had 
hitherto  been  regarded  as  individual  animals,  or  medusa; 
with  a  multiplicity  of  organs;  further  study  proved  that 
each  of  these  apparent  organs  is  really  a  modified  me- 
dusa, and  the  whole  united  structure  a  stem.  This 
example  throws  a  good  deal  of  light  on  the  important 
question  of  association  and  division  of  labor.  The  whole 
floating  siphonophoron  is,  physiologically  considered  (in 
respect  of  its  vital  activity),  a  harmoniously  organized 
animal  with  a  number  of  different  organs ;  but  from  the 
morphological  point  of  view  (in  respect  of  form  and 
structure)  each  dependent  organ  is  really  an  indepen- 
dent medusa. 

It  is  clear,  from  these  few  illustrations,  that  the  ques- 
tion of  organic  individuality  is  by  no  means  so  simple 
as  it  seems  at  first  sight,  and  that  it  receives  different 
answers  according  as  we  look  at  the  form  and  structure 
(morphologically)  or  the  vital  and  psychic  activity 
(physiologically).  We  must,  therefore,  distinguish  at 
once  between  morphological  (niorphonta)  and  physio- 
logical (bionta)  individuals.  The  tree  and  the  siphono- 
phoron are  bionta,  or  individuals  of  the  highest  order, 
made  up  of  a  number  of  similar  branches  or  persons, 
the  social  morphonta.  But,  when  we  further  dissect 
the  latter  anatomically  into  their  various  organs,  and 
these  again  into  their  microscopic  elements,  the  cells, 
each  branch  or  person  seems  to  be  a  bion,  and  their 
^cells  to  be  morphonta.  Each  multicellular  organism 
1  is,  however,  developed  in  the  beginning  from  a  single 
cell,  the  stem-cell  (cytula)  or  fertilized  ovum;  this  is  at 
once  a  morphon  and  a  bion,  a  simple  individual  both 
morphologically  and  physiologically.  The  whole  proc- 
ess of  its  development  into  a  multicellular  organism  con- 
sists in  a  repeated  cleavage  of  the  stem-cell,  the  resultant 

149 


THE    WONDERS    OF    LIFE 

I  cells  being  joined  in  a  higher  unity,  and  assuming  dif- 
I  1  ferent  forms  in  consequence  of  the  division  of  work. 
—  The  complicated  modern  state,  with  its  remarkable 
achievements,  may  be  regarded  as  the  highest  stage  of 
individual  perfection  which  is  known  to  us  in  organic 
nature.  But  we  can  only  understand  the  structure  of 
this  extremely  complex  "organism  of  the  highest  order," 
and  its  social  forms  and  functions,  when  we  have  a 
sociological  knowledge  of  the  various  classes  that  com- 
pose it,  and  the  laws  of  their  association  and  division  of 
labor;  and  when  we  have  made  an  anthropological 
study  of  the  nature  of  the  persons  who  have  united, 
under  the  same  laws,  for  the  formation  of  a  community 
and  are  distributed  in  its  various  classes.  The  familiar 
arrangement  of  these  classes,  and  the  settling  of  the 
rank  in  the  mass  and  the  governing  body,  show  us  how 
this  complex  social  organism  is  built  up  step  by  step. 

But  we  have  to  look  in  the  same  way  on  the  cell-state, 
which  is  made  up  from  the  separate  individualities  in 
human  society  or  in  the  kingdom  of  the  tissue-animals, 
or  the  branches  in  the  kingdom  of  the  tissue-plants. 
Their  complex  organism,  composed  of  various  organs 
and  tissues,  can  only  be  understood  when  we  are  ac- 
quainted with  their  constituent  elements,  the  cells, 
and  the  laws  according  to  which  these  elementary  organ- 
isms unite  to  form  cell-communities  and  tissues,  and  are 
in  turn  modified  in  the  divers  organs  in  the  division  of 
labor.  We  must,  therefore,  first  establish  the  scale  of 
the  morphonta,  and  the  laws  of  their  association  and 
ergonomy,  according  to  which  the  several  stages  or  con- 
ditions of  morphological  individuality  build  on  each 
other.  Three  such  stages  may  be  at  once  distinguished: 
(i)  the  cell  (or,  more  correctly,  the  plastid),  (2)  the  person 
(anim^al)  or  branch  (vegetal),  and  (3)  the  stem  or  cormus. 
But  we  shall  find  that  there  are  further  subordinate 
stages  under  each  of  these  three.     It  is  only  in  the  case 

150 


UNITIES    OF    LIFE 

of  the  protists  that  the  morphological  unity  is  bound  up 
with  the  physiological.  In  the  case  of  the  histona, 
the  multicellular,  tissue-forming  organisms,  this  is  only 
so  at  the  beginning  of  individual  existence  (at  the 
stage  of  the  stem-cell).  As  soon  as  the  multicellular 
body  arises  from  this  cytula  by  repeated  segmentation,  it 
is  raised  to  the  stage  of  a  higher  individuality,  the  cell- 
state. 

Our  own  human  frame  is,  in  its  mature  condition,  like 
that  of  all  the  higher  animals,  a  very  complete  cell-state, 
but  a  single  cell  at  the  beginning  of  its  existence.  We 
speak  of  the  life-unity  of  the  former  as  an  actual  bion, 
and  that  of  the  latter  as  a  virtual  bion;  in  other  words, 
the  physiological  individual  or  the  life-unity  has  in  the 
first  case  reached  the  highest  stage  of  individual  develop- 
ment that  pertains  to  its  species,  while  in  the  second 
case  it  remains  at  the  lowest  stage  of  virtual  formation, 
and  has  only  the  capacity  of  rising  to  the  higher  stage. 
In  the  higher  plants  and  animals  only  one  cell  of  the 
organism,  or  the  two  combined  sexual  cells  (ovum  and 
spermium),  are  the  potential  bion  which  may  develop 
into  an  actual  one.  There  are,  however,  exceptions.  In 
the  fresh-water  polyp  (hydra)  and  cognate  cnidaria  each 
piece  of  the  body-wall,  in  the  bath-sponge  (euspongia) 
and  similar  sponges  each  piece  of  tissue,  and  in  many 
plants  (for  instance,  marchantia  among  the  crytogams 
and  bryophyllum  among  the  phanerogams)  each  portion 
of  a  branch  or  leaf,  has  the  power  to  develop  into  a 
mature  organism,  and  is,  therefore,  a  virtual  bion. 

From  these  virtual  bionta  (parts  of  the  body  that  may 
grow  into  whole  organisms)  we  must  distinguish  the 
partial  bionta  which  have  not  this  property.  These  are 
separated  parts  of  the  body  that  live  for  a  time  after 
being  cut  off  from  the  whole  organism,  but  then  die  off. 
Thus,  for  instance,  the  heart  of  a  tortoise  beats  for  a 
long  time  after  being  cut  out.    A  flower  that  has  been 


THE    WONDERS    OF    LIFE 

plucked  may,  if  put  in  water,  keep  fresh  and  alive  for 
many  days.  In  some  highly  organized  cephalopods  one 
of  the  eight  arms  of  the  male  develops  into  an  inde- 
pendent body,  swims  about,  and  accomplishes  the 
fertilization  of  the  female  {hcctocotylus  among  the 
argonaiita,  pkilonexis,  etc.).  It  was  at  first  thought  to 
be  an  independent  animal  parasite.  The  samie  thing 
happens  with  the  remarkable  foldlike  dorsal  append- 
ages of  a  large  naked  snail  (thetys),  which  get  detached 
and  creep  about.  The  body  of  many  of  the  lower 
animals  may  be  cut  in  pieces  and  yet  may  live  for  weeks. 
The  life-properties  of  these  partial  bionta  are  important 
in  view  of  the  general  question  of  the  nature  of  life  and 
its  apparent  unity  in  most  of  the  higher  organisms.  As  a 
fact,  even  here  the  cells  and  organs  lead  their  separate 
individual  life,  though  they  are  subordinate  to  and 
dependent  on  the  whole. 

It  has  been  attempted  to  answer  this  question  of 
organic  individuality  in  the  sense  of  counting  all  or- 
ganisms individuals  which  develop  from  a  single  fer- 
tilized ovum.  Thus,  the  Italian  botanist  Gallesio,  in 
1816,  regarded  all  plants  that  arise  by  asexual  generation 
(budding  or  segmentation) — sprouts,  branches,  slips, 
bulbs,  etc. — as  merely  portions  of  a  single  individual 
that  came  from  an  egg  (the  seed).  So  also  Huxley,  in 
1855,  considered  the  sum  of  all  the  animals  that  have 
been  produced  by  asexual  propagation,  but  from  a  single 
sexually  generated  animal,  to  be  parts  of  one  individual. 
In  practice,  however,  this  principle  is  useless.  We 
should  have  to  say  that  the  millions  of  plant-hce  which 
arise  parthenogenetically  from  unfertilized  germ-cells, 
but  are  originally  descended  from  one  impregnated 
ovum,  are  one  single  individual;  so  also  all  the  weeping- 
willows  in  Europe,  because  they  all  came  from  shoots  of 
one  single  sexually-produced  tree. 

Many  attempts  have  been  made  in  the  course  of  the 


UNITIES    OF    L  I  1"  E 

nineteenth  century  to  give  a  generally  satisfactory  an- 
swer to  this  ditticult  question  of  the  coni£;nt  and  CDja- 
notation  of  the  idea^of  the  organic  individual.  None  of 
these  has  found  general  favoi\  I  have  compared  and 
criticised  them  in  the  third  book  of  my  General  Mor- 
pJwlogy.  I  there  paid  special  attention  to  the  views  of 
Goethe,  Alexander  Braun,  and  Nageli  among  the  bota- 
nists, and  Johannes  Miiller,  Leuckart,  and  Victor  Carus 
among  the  zoologists.  When  we  consider  the  striking 
divergence  of  the  views  of  such  distinguished  scientists 
and  thinkers  on  so  important  a  biological  question,  we 
can  understand  that  opinions  are  still  very  divided  to- 
day. Hence  we  must  not  be  too  hard  on  the  meta- 
physical philosophers  when — in  complete  ignorance  of 
the  real  facts  —  they  rear  the  most  extraordinary 
theories  in  their  airy  speculations  on  "the  principle 
of  individuation  "  Compare,  for  instance,  the  opinions 
of  the  school-men  and  those  of  recent  thinkers  such  as 
Arthur  Schopenhauer  and  Edward  Hartmann.  As  a 
rule,  the  psychological  side  of  the  problem — the  question 
of  the  individual  soul  —  is  very  promiinent,  without 
much  attention  being  paid  to  its  material  substratum 
— the  anatomic  basis  of  the  organism.  Many  meta- 
physicians, who,  in  their  one-sided  anthropism,  make 
man  here  also  the  measure  of  all  things,  would  assign 
personal  consciousness  as  the  basis  of  the  idea  of  in- 
dividuality. It  is  obvious  that  this  is  not  a  practicable 
test  even  for  the  higher  animals,  to  say  nothing  of  the 
lower  animals  and  plants.  In  these  we  have  a  far 
greater  variety  of  individuality  on  the  one  hand,  and  a 
far  greater  simplicity  of  construction  on  the  other.  I 
have  tried  to  show,  in  my  essay  on  "  The  Individuality  of 
the  Animal  Body"  (1878),  the  easiest  way  to  answer  these 
complicated  tectological  questions,  and  to  support  it  by 
the  science  of  structure.  It  suffices  to  distinguish  the 
three  chief  stages   I   have  mentioned,   and   to  explain 

153 


THE    WONDERS    OF    LIFE 

clearly  their  physiological  significance  on  the  one  hand 
and  morphological  on  the  other.  We  will  therefore 
consider  the  cell  first,  then  the  person  (or  sprout),  and, 
finally,  the  stock  (or  cornius). 

Ever  since  the  middle  of  the  nineteenth  century  the 
cell  theory  has  been  generally  and  rightly  considered 
one  of  the  most  important  theories  in  biology.  Every 
anatomical,  histological,  physiological,  and  ontogenetic 
work  must  build  on  the  idea  of  the  cell  as  the  elementary 
organism.  Nevertheless,  we  are  still  very  far  from 
having  a  general  and  clear  agreement  as  to  this  univer- 
sal and  fundamental  idea.  On  the  contrary,  the  ablest 
biologists  still  difi;er  considerably  as  to  the  nature  of  the 
cell  or  the  elementary  individual,  its  relation  to  the 
whole  of  the  multicellular  organism,  and  so  on.  This 
divergence  of  views  is  partly  due  to  the  intricacy  of 
the  phenomena  we  find  in  the  life  of  the  cell,  and  partly 
to  the  many  and  extensive  changes  that  have  been  made 
in  the  meaning  of  the  term  in  the  course  of  its  employ- 
ment. Let  us  first  cast  a  glance  at  the  various  stages 
of  its  history. 

When  in  the  last  third  of  the  seventeenth  century  a 

V     number  of  scientists,  especially  Malpighi  in  Italy  and 

^       Crew  in  England,  used  the  microscope  for  the  first  time 

in  the  anatomic  study  of  plant  structure,  they  notjced  a 

certain  build  of  the  tissue  that  closely  resembled  the 

honeycomb.     The  closely  packed  wax  cells,  filled  with 

honey,  of  the  hive,  which  show  a  hexagonal  appearance 

in  section,  are  like  the  wood  cells  that  contain  the  sap  in 

/"     the  plant.     It  was  the  great  merit  of  Schleiden,  the  real 

founder  of  the  cell  theory,  to  prove  that  all  the  different 

tissues  of  plants  are  originally  composed  of  such  cells 

V(i838).  Theodor  Schwann  soon  afterwards  proved  the 
same  for  the  animal  tissues;  in  1839  he  extended  the 
theory  to  the  whole  organic  world.  Both  these  scientists 
regarded  the  cell  as  essentially  a  vesicle,  the  firm  mem- 

154 


UNITIES    OF    LIFE 

brane  of  which  enclosed  a  fluid  content,  and  a  soHd 
smaller  body  inside  this,  which  R.  Brown  had  recognized 
as  the  nucleus  in  1833.  They  compared  the  cell,  as  a 
microscopic  individual,  to  an  organic  crystal,  and 
thought  it  aro^e  by  aTsort  of  crystallization  in  an  organic 
medium  (cytoblastema) ;  in  this  the  central  nucleus 
would  serve  as  starting-point  like  the  nucleus  of  the 
crystal. 

In  the  first  twenty  years  (1839-59)  of  the  cell  theory 
it  was  a  fixed  principle  that  there  were  three  essential 
parts,  of  the  cell.     Firstly,  there  was  the  strong  outer  (ii 
membrane,  which  was  not  only  regard^ed  as  a  protective 
covering,  but  also  credited  with  a  great  deal  of  impor- 
tance as  an  element  in  the  building  of  the  organism.     In     . 
the  second  place,  there  was  the  fluid  or  semi-fluid  con- 
tent (the  sap);  and,  thirdly,  the  firm  nucleus  enclosed  A^ 
in  the  sap.     In  order  to  give  a  clearer  idea  of  the  rela- 
tive thickness  and  disposition  of  these  parts,  the  cell 
was  compared  to  a  cherry  or  a  plum.     The  soft  flesh  of 
this  fruit  (corresponding  to  the  cell  sap)  can,  with  diffi- 
culty, be  separated  from  the  external  firm  skin  or  from 
the  hard  stone  within.     A  great  step  in  advance  was 
made   in    i860,   when   Max   Sch\iJtze   showed   that   the 
external  mernbrane  was  an  unessential  and  secondarily 
formed  part  of  the  cell.     It  is,   as  a  fact,   altogether 
wanting  in  many,  especially  young,  cells  of  the  animal 
body.  They  are  naked  cells  without  any  membrane.   The 
distinguished  anatomist  also  proved  that  the  co-called 
"cell  sap" — the  real  body  of  the  cell — is  n^t  a  simple 
fluid,  but  a  viscous,  albuminous    substance,  the   inde- 
pendent movements  of  which  had  long  been  known  in 
the  rhizopods,  and  which  the  first  to  study  it  carefully, 
Felix  Dujardin,  had  described  as  sarcodc  in  1835.     ^^^^^ 
Schultze  further  showed  that  this  '*sarcode"  was  iden- 
tical with  the  "cell  mucus"  of  the  ])lant  cells  which 
Hugo  Mohl  had  designated  "proto^sm"  in  1846,  and 

~      155 


THE    WONDERS    OF    LIFE 

that  this  Hving  matter  must  be  regarded  as  the  real 
vehicle  of  the  phenomena  of  Hfe.  As  the  membrane 
was  now  recognized  to  be  non-essential,  of  secondary 
growth,  and  completely  w^  an  ting  in  some  cases,  there 
remained  only  two  essential  parts  of  the  cell — the  outer 
soft  cell  body,  consisting  of  protoplasm,  and  the  inner 
firm  nucleus,  consisting  of  a  similar  substance  called 
nuclein.  The  original  naked  cell  was  now  like  a  cherry 
or  plum  without  the  skin.  This  new  idea  of  the  cell, 
formulated  forty  years  ago,  which  I  endeavored  to  con- 
firm in  my  monograph  on  the  radiolaria  (1862),  is  now 
generally  accepted,  and  the  cell  is  defined  as  a  granule 
or  particle  of  protoplasm  (=  cytoplasm)  enclosing  a  firm 
and  definite  nucleus  (or  caryon,  consisting  of  caryoplasm). 
This  would  be  a  good  occasion  to  glance  at  the  errors 
to  which  microscopic  investigation  and  the  conclusions 
based  on  it  are  liable.  Although  Kolliker  in  1845,  ^^^ 
Remak  in  185 1,  had  drawn  attention  to  the  existence  of 
naked  cells,  and  had  compared  their  movements  (for 
instance,  in  lymph-cells)  to  those  of  the  protoplasm  in 
plant-cells,  the  majority  of  the  leading  microscopists 
clung  for  twenty  years  to  the  dogma  that  every  cell 
must  have  a  membrane ;  the  definite  outline  which  even 
a  naked  cell  must  show  in  a  different  refxacting  medium 
was  taken  to  be  the  sign  of  a  special  and  anatomically 
separable  membrane.  It  would  be  just  as  correct  to 
talk  of  a  protective  membrane  on  a  homogeneous  glass 
ball;  its  outline  is  sharply  defined.  In  the  long  contro- 
versy that  "exact"  observers  sustained  as  to  the  pres- 
ence or  absence  of  a  membrane,  this  optical  error — the 
false  interpretation  of  a  sharp  contour — counted  for  a 
good  deal.  It  is  much  the  same  with  other  conflicts  of 
"exact "  observers  who  give  their  "certain  observations " 
as  facts,  whereas  they  are  really  inferences  from  imper- 
fect observations  on  which  different  interpretations  may 
be  put. 

156 


U  N  1  T  1  r:  S    OF    LIFE 

Forty  years  ago  (1S64)  I  tried  in  vain  to  detect  a 
nucleus  in  the  naked,  living,  mobile  protoplasm  of  a 
few  small  rhizopod-like  protists  (protamocba  and  proto- 
genes).  Other  observers,  who  afterwards  studied  simi- 
lar unnucleated  cells  (Gruber,  Cienkowski,  and  others), 
were  no  more  successful.  On  the  ground  of  these  ob- 
servations, which  were  often  repeated  afterwards,  I 
formed  the  class  of  the  nioncra — the  simplest  unnucleated 
organjsms  —  in  my  General  Morphology  in  1866,  and 
pointed  out  their  great  importance  in  solving  some  of 
the  chief  problems  of  biology.  This  importance  has 
been  much  enhanced  of  late,  since  the  chromacea  and 
bacteria  have  also  been  recognized  as  unnucleated  cells. 
Biitschli  has,  it  is  true,  raised  the  objection  that  their 
homogeneous  plasma-body  behaves,  not  as  cytoplasm, 
but  as  caryoplasm  (or  nuclein),  and  so  that  these  sim- 
plest plastids  correspond,  not  to  the  cell-body,  but  to 
the  nucleus  of  other  cells.  On  this  view  the  bacteria 
and  chromacea  are  not  cells  without  nuclei,  but  nuclei 
without  cell-bodies.  This  idea  agrees  with  my  own  in 
conceiving  the  plasma-body  of  the  monera  (apart  from 
its  molecular  structure)  as  homogeneous  and  not  yet  ad- 
vanced as  far  as  the  characteristic  differentiation  of  in- 
ner nucleus  and  outer  cell-body.  Bearing  in  mind  that 
these  essential  parts  of  the  cell  (in  the  view  of  most 
cytologists)  are  chemically  related  yet  different  from 
each  other,  we  have  three  possible  cases  of  the  original 
formation  of  the  nucleated  cell  from  the  unnucleated 
cytode:  (i)  The  nucleus  and  cell-body  have  arisen  by 
dififerentiation  of  a  homogeneous  plasm  (monera);  (2) 
the  cell-body  is  a  secondary  growth  from  the  primary 
nucleus;  (3)  the  nucleus  is  a  secondary  development 
from  the  cell-body. 

On  the  first  view,  which  I  hold,  the  plaspa.  or  living 
matter,  of  the  earliest  organisms  on  the  earth  (which 
can  only  be  conceived  as  archigonous  monera)  was  a 

157 


THE    WONDERS    OF    LIFE 

homogeneous  plasson  or  archiplasm — that  is  tc  say,  a 
plasma -compound  that  was  not  yet  differentiated  into 
outer  cytoplasm  and  inner  caryoplasm.  The  rise  of  this 
chemical  distinction — and  the  accompanying  morpho- 
logical division  of  cell-body  and  nucleus — was  due  to  a 
phyletic  differentiation;  it  was  the  outcome  of  a  very 
early  and  most  important  division  of  labor.  The  hered- 
itary matter  gathered  in  the  nucleus,  the  outer  cell- 
matter  controlling  the  intercourse  with  the  external 
world.  Thus,  by  this  first  ergonomy,  the  nucleus  be- 
came the  vehicle  of  heredity  and  the  cell-body  the  organ 
of  adaptation.  Opposed  to  this  view  is  the  second,  the 
hypothesis  which  the  founder  of  the  cell-theory,  Schlei- 
den,  had  put  forward — that  the  nucleus  is  the  original 
base  of  the  cell,  and  the  cell-body  a  secondary  develop- 
ment from  it.  This  opinion  (which,  in  the  main,  cor- 
responds to  that  of  Biitschli)  raises  a  number  of 
difficulties;  as  does  also  the  third  hypothesis,  that  the 
unnucleated  "protoplasm-body"  (the  outer  cytoplasm- 
body)  is  the  original  formation,  and  that  the  nucleus 
arose  secondarily  by  condensation  and  chemical  modi- 
fication of  it.  At  the  bottom,  however,  the  difference 
between  the  three  hypotheses  on  the  primary  cytogene- 
sis  is  not  as  great  as  it  seems  at  first  sight.  However,  I 
am  more  inclined  to  adhere  to  the  first ;  it  supposes  that 
the  physiological  and  chemical  differences  between 
nucleus  and  cell-body,  which  afterwards  became  so  im- 
portant, were  not  originally  present.  The  phenomena 
of  caryolysis  in  indirect  cell-division  show  us  still  how 
close  are  the  relations  of  the  two  substances. 

If  the  organic  population  of  our  planet  has  arisen 
naturally,  and  not  by  a  miracle,  as  Reinke  and  other 
vitalists  suppose,  the  earliest  elementary  organisms, 
produced  by  the  chemical  process  of  archigony  (spon- 
taneous generation),  could  not  be  real  nucleated  cells, 
but  unnucleated  cytodes  of  the  type  of  the  chromacea 

158 


UNITIES    OF    LIFE 

(cf.  chapter  ii.).  The  nucleated  real  cell,  as  Oscar  Hert- 
wig  and  others  define  it  to-day,  can  only  have  arisen  by 
phylogenetic  differentiation  of  nucleus  and  cell-body 
from  the  simple  cytode  of  the  monera.  In  that  case  it 
is  a  matter  of  simy^le  logic  to  distinguish  the  older  cytode 
from  the  later  cell.  The  two  may  then  best  be  com- 
prised (as  I  proposed  in  vain  in  1866)  under  the  name 
of  "plastids"  (formative  principles) — that  is,  the  ele- 
mentary organism  in  the  broader  sense.  But  if  it  is 
preferred  to  call  the  latter  cells  (in  the  broader  sense), 
the  wrong  modern  idea  of  the  cell  must  be  altered,  and 
the  nucleus-feature  omitted  from  it.  The  cell  is  then 
simply  the  living  particle  of  plasm,  and  its  two  stages 
of  development  must  be  described  by  other  names. 
The  unnucleated  plastid  might  be  called  primitive  cell 
(protocytos),  and  the  ordinary  nucleated  one  the  nuclear 
cell  (caryocytos). 

A  long  gradation  of  cellular  organization  leads  from 
the  simplest  primitive  cells  (monera)  to  the  highest 
developed  protists.  While  no  morphological  organiza- 
tion whatever  is  discoverable  in  the  homogeneous 
plasma-body  of  the  chromacea  and  bacteria,  we  find  a 
composition  from  different  parts  in  the  highly  differen- 
tiated body  of  the  advanced  protophyta  (diatomes, 
siphonea)  and  protozoa  (radiolaria,  infusoria).  The 
manifold  j^arts  of  the  unicellular  organism,  developed 
by  division  of  work  in  the  plasm,  discharge  various 
functions,  and  behave  physiologically  like  the  organs  of 
the  multicellular  histona.  But  as  the  idea  of  "organ" 
in  the  latter  is  morphologically  fixed  as  a  multicellular 
part  of  the  body,  made  up  of  numerous  tissues,  we  can- 
not call  these  similarly  functioning  parts  "organs  of 
the  cell,"  and  had  better  describe  them  as  organella  (or 
organoids). 

The  great  majority  of  the  protists  are,  in  the  devel- 
oped condition,  as  actual  individuals,  equivalent  mor- 

159 


THE    WONDERS    OF    LIFE 

pliologically  to  real  nucleated  cells.  By  means  of  adap- 
tation to  the  most  varied  conditions  and  the  inheritance 
of  the  properties  thus  acquired  such  a  variety  of  uni- 
cellular forms  has  been  evolved  in  the  course  of  millions 
of  years  that  we  can  distinguish  thousands  of  living 
species,  both  of  plasmodomous  protophyta  and  plas- 
mophagous  protozoa.  The  number  of  known  and 
named  species  is  already  as  high  as  this  in  several  dis- 
tinct classes,  as,  for  instance,  in  the  diatomes  of  the 
primitive  plants  and  the  radiolaria  of  the  primitive  ani- 
mals. These  solitary  living  unicellulars,  or  "hermit- 
cells,"  may  be  called  monohia. 

Many  other  protists  have  abandoned  this  original 
solitary  life;  they  follow  their  social  instincts  and  form 
communities  or  colonies  of  cells  (ccFnobia).  These  are 
usually  formed  by  the  daughter-cells  which  arise  from 
the  cleavage  of  a  mother-cell  remaining  united  after  the 
division,  and  so  on  with  the  succeeding  generations 
which  come  from  their  repeated  segmentation.  The 
following  are  the  chief  forms  of  these  coenobia : 

1.  Gelatinous  Ccenobia. — The  social  cells  secrete  a 
structureless  mass  of  jelly,  and  remain  associated  in 
the  common  gelatinous  mass,  without  actual  contact. 
Sometimes  they  are  regularly,  at  other  times  irregular- 
ly, distributed  in  it.  We  find  coenobia  of  this  kind  even 
among  the  monera,  such  as  the  zoogloea  of  many  bacteria 
and  chromacea.  They  are  common  among  the  proto- 
phyta and  protozoa. 

2.  Spherical  Ccenobia. — The  cell-community  forms 
a  sort  of  ball,  the  cells  lying  close  together  at  its  surface, 
touching  each  other  or  even  forming  a  continuous  layer ; 
such  are  holosphcura  and  volvox  among  the  protophyta, 
magosphcera  and  synura  among  the  protozoa.  The  lat- 
ter are  particularly  interesting  because  they  resemble 
the  blastiila,  an  important  embryological  stage  of  the 
metazoa,  of  which  the  simple,  epithelial  cell-layer  at 

i6o 


UNITIES    OF    LIFE 

the  surface  of  the  hollow  sphere  is  called  the  blastoderm 
(or  germinal  membrane). 

3.  Arboreal  Ccenobia. — The  cell-community  takes 
the  form  of  a  small  tree  or  shrub,  the  fixed  cells  secret- 
ing jelly-like  stalks  at  their  base  and  these  forming 
branches.  At  the  top  of  each  stalk  or  branch  is  an  in- 
dependent cell;  so  in  the  case  of  the  gomphoncma  and 
many  other  diatomes,  the  codonocladium  among  the 
flagellata,  and  the  carchcsinm  among  the  ciliata. 

4.  Catenal  Ccenobia. — The  cell-community  forms  a 
chain,  the  links  of  which  (the  individual  cells)  are  joined 
in  a  row.  We  find  chainlike  cell-communities  of  this 
sort,  or  "articulated  threads,"  even  among  the  monera 
{oscillaria  and  nostic  among  the  chromacea,  leptothrix 
among  the  bacteria).  Among  the  diatomes  we  have  the 
bacillaria,  among  the  thalamophora  nodosaria,  as  ex- 
amples. Many  of  the  lower  protophyta  (algaria  and 
algetta)  form  the  direct  transition  to  the  true  alga^ 
among  the  metaphyta,  as  the  threadlike  layer  of  the 
latter  (for  instance,  ciadophora)  is  only  a  higher  develop- 
ment of  the  catenal  coenobium,  with  polymorphism  of 
the  co-ordinated  cells.  We  may  also  regard  these  ar- 
ticulated multicellular  threads  as  the  first  sketch  for  the 
formation  of  tissues  in  the  metaphyta. 

The  stable  communities  of  cells  which  make  up  the 
body  of  the  histona,  or  multicellular  plants  and  animals, 
are  called  tissues  (tela  or  hista).  They  differ  from  the 
ccenobia  of  the  protists  in  that  the  social  cells  give  up 
their  independence,  assume  different  forms  in  the  divi- 
sion of  labor,  and  subordinate  themselves  to  the  higher 
unity  of  the  organ.  However,  it  would  be  just  as  diffi- 
cult to  lay  down  a  sharp  limit  between  the  ccenobia  and 
the  tissues  as  between  the  protists  and  the  histona  which 
possess  them;  the  latter  have  been  developed  phylo- 
genetically  from  the  former.  The  original  physiological 
independence  of  the  cells  which  have  combined  to  form 
II  t6i 


THE    WONDERS    OF    LIFE 

tissues  is  more  completely  lost  in  proportion  to  the 
closeness  of  their  combination,  the  complexity  of  their 
division  of  labor,  and  the  differentiation  and  centraliza- 
tion of  the  tissue-organism.  Hence  the  various  kinds 
of  tissue  in  the  body  of  the  histona  behave  like  the  va- 
rious classes  and  professions  in  a  state.  The  higher  the 
civilization  and  the  more  varied  the  classes  of  workers, 
the  more  they  are  dependent  on  each  other,  and  the 
state  is  centralized. 

In  the  lower  tissue-forming  plants,  the  algae  and  fungi, 
the  plant-body  has  the  appearance  of  a  layer  of  cells, 
the  tissues  of  which  show  little  or  no  division  of  labor. 
In  these  thallophyta  there  are  none  of  the  conducting  or 
vascular  fibres,  the  formation  of  which  is  of  great  im- 
portance in  the  higher  plants  in  connection  with  their 
physiological  function  of  circulation  of  the  sap.  These 
more  advanced  vascular  plants  comprehend  the  two 
great  groups  of  ferns  (pteridophyta)  and  flowering  plants 
{anthophyta,  or  phanerogams).  Their  body  is  always 
composed  of  two  chief  organs,  the  axial  stem  and  the 
lateral  leaves.  This  is  also  the  case  with  the  mosses 
(bryophyta),  which  have  no  vascular  fibres;  they  lie  be- 
tween the  two  chief  groups  of  the  non-vascular  thal- 
lophyta and  the  vascular  cormophyta.  However,  this 
histological  and  organological  division  of  the  two  great 
groups  of  tissue-plants  must  not  be  pressed;  there  are 
many  exceptions  and  intermediate  forms.  In  general 
their  manifold  tissue-forms  may  be  brought  under  two 
chief  groups,  which  we  may  call  primary  and  secondary. 
The  primary  tissues  are  the  phylogenetically  older  and 
histologically  simple  "cell-tissues,"  such  as  we  have  in 
the  thallophyta  (algae,  fungi,  and  mosses) ;  in  these  there 
are  no  conducting  fibres,  or,  at  least,  only  rudimentary 
ones.  The  secondary  tissues  are  a  later  development 
from  these;  they  form  conducting  and  vascular  fibres 
and  other  highly  differentiated  forms  of  tissue  (cam- 

162 


UNITIES    OF    LIFE 

bium,  wood,  etc.).  They  make  up  the  bodies  of  the 
more  complex  vascular  plants,  the  ferns  and  flowering 
plants. 

In  the  bodies  of  the  tissue-animals  we  may  similarly 
distinguish  two  chief  groups  of  tissues,  the  primary  and 
secondary.  The  former  are  phylogenetically  and  onto- 
genetically  older  than  the  latter.  The  primary  tissues 
of  the  metazoa  are  the  cpitclia,  simple  layers  of  cells  or 
forms  of  tissue  directly  derived  from  such  (glands,  etc.). 
Secondary  tissues,  evolved  from  the  former  by  physio- 
logical change  of  work  and  morphological  differentia- 
tion, are  the  apotclia;  of  these  "derivative  tissues"  we 
may  distinguish  the  three  leading  groups  of  connective 
tissue,  muscular  tissue,  and  nerve  tissue.  These  three 
great  groups  of  tissue  in  the  animal  world  may  be  sub- 
divided, like  the  plant  groups,  into  lower  and  higher 
sub-sections.  The  coelenteria  (gastraeads,  sponges,  cni- 
daria)  are  predominantly  built  up  of  epitelia,  as  are  also 
the  phyletically  older  group  of  the  coelomaria ;  in  the  vast 
majority  of  the  latter,  however,  the  great  mass  of  the 
body  is  formed  of  apotelia,  and  they  are  subject  to  the 
most  extensive  differentiation.  The  embryo  of  all  the 
metazoa  consists  solely  of  epitelia  (the  germ-layers)  at 
first;  apotelia  are  developed  from  these  afterwards  by 
differentiation  of  the  tissues. 

Comparative  anatomy  distinguishes  in  the  multi- 
cellular body  of  the  tissue-forming  organisms  a  great 
number  of  different  parts,  which  are  regularly  adapted 
to  discharge  definite  vital  functions,  and  have  been 
most  intricately  developed  in  virtue  of  the  division  of 
labor.  They  are  called  "organs"  in  the  stricter  sense 
in  opposition  to  the  organella  (or  organoids)  of  the  pro- 
tists;  the  latter  have,  it  is  true,  a  similar  physiological 
purport,  but  are  not  (being  parts  of  a  cell)  equal  to 
the  former  morphologically.  The  remarkable  efficiency 
that  we  find  in  the  structure  of  the  various  organs  in 

163 


THE    WONDERS    OF    LIFE 

view  of  the  functions  they  have  to  discharge,  and  the 
regularity  of  their  construction  in  the  unity  of  the  his- 
ton — in  other  words,  their  adaptive  organization — is 
explained  mechanically  by  the  theory  of  selection,  while 
the  teleological  hypotheses  of  dualistic  biology  (for  in- 
stance, the  "intelligent  dominants"  of  Reinke)  com- 
pletely fail  to  account  for  their  origin.  The  gradual 
advance  of  the  organs  and  their  physiological  division 
of  labor  have  many  analogies  in  the  two  kingdoms  of 
the  histona.  While  at  the  lowest  stages  the  simple 
organ  represents  only  a  separate  individual  piece  of 
primitive  tissue,  we  find  special  systems  of  organs  and 
organic  apparatus  in  the  higher  stages. 

The  idea  of  a  particular  system  of  organs  is  deter- 
mined by  the  unity  of  one  tissue  which  forms  the  char- 
acteristic element  in  the  totality  of  the  organs  that  be- 
long to  it.  Of  such  systems  in  the  kingdom  of  the 
metaphyta  we  have:  the  skin-system  (with  the  tissue 
of  the  epidermis),  the  vascular  system  (with  its  con- 
ducting and  vascular  fibres),  and  the  complementary 
tissue  system  (with  the  basic  tissue).  In  the  kingdom 
of  the  metazoa  we  may  similarly  distinguish:  the  skin- 
system  (integument  of  the  epidermis),  the  vascular  sys- 
tem (with  the  mesenchyma-tissue  of  the  blood  and 
blood-vessels),  the  muscular  system  (with  the  muscle- 
tissue),  and  the  nervous  system  (with  the  neurona  of 
the  nerve-tissue). 

In  contrast  with  the  histological  idea  of  a  system  of 
organs,  we  have  the  physiological  conception  of  an  ap- 
paratus of  organs.  This  is  not  determined  by  the  unity 
of  the  constituent  tissue,  but  by  the  unity  of  the  life- 
work  that  is  accomplished  by  the  particular  group  of 
organs  in  the  histona.  Such  an  apparatus  of  organs  is, 
for  instance,  the  flowers  and  the  fruit  developing  there- 
from in  the  phanerogams,  or  the  eye  or  the  gut  of  an 
animal.     In  these  apparatus  the  most  diverse  organs 

164 


UNITIES    OF    LIFE 

and  systems  of  organs  may  be  associated  for  the  fulfil- 
ment of  a  definite  physiological  task. 

In  the  higher  animals  and  plants  we  usually  regard  as 
the  "real  individual"  (in  the  wider  sense  of  the  word) 
the  tissue-forming  organism  made  up  of  various  organs ; 
and  we  may  here  briefly  and  instructively  call  this  the 
histonal  individual  (or,  more  briefly,  the  "histonal"). 
Botanists  call  this  individual  phenomenon  among  the 
metaphyta  a  sprout  (blastiis).  Zoologists  give  the  title 
of  "person"  {prosopon)  to  the  corresponding  unity 
among  the  animals.  The  two  forms  agree  very  much  in 
their  general  features,  and  may  be  called  "individuals 
of  the  second  order,"  if  we  take  the  cells  to  be  the  first 
and  the  stock  the  third  stage  in  the  hierarchy  of  or- 
ganic individuality.  In  comprising  them  here  under  the 
general  head  of  histonals,  or  histonal  individuals,  I  mean 
by  this  to  designate  the  definite  physiological  unity  of 
the  multicellular  and  tissue-forming  organism,  as  con- 
trasted with  the  unicellular  protist  on  the  one  hand,  and 
the  higher  stem,  made  up  of  several  histonals,  on  the 
other. 

The  plant-histonal,  which  Alexander  Braun  especially 
clearly  marked  out  and  described  as  the  sprout,  is  found 
in  two  principal  forms  in  the  kingdom  of  the  metaphyta 
— the  lower  form  of  the  layer-sprout  {thalliis)  and  the 
higher  form  of  the  stalk-sprout  {cnlniiis).  The  thallus 
predominates  in  the  lower  and  older  sub-kingdom  of  the 
layer-plants  {thallo phyta) ,  in  the  classes  of  the  algas  and 
fungi;  the  culmus  in  the  higher  and  younger  sub-king- 
dom of  the  stalk-plants  UoruiopJiyta),  in  the  classes  of 
the  mosses,  ferns,  and  flowering  plants.  The  culmus 
presents  in  general  the  characteristic  form  of  an  axial 
central  organ,  the  stalk,  with  lateral  organs,  the  leaves, 
attached  to  this  at  the  sides,  the  former  having  an  un- 
limited vertical  growth  and  the  latter  an  unlimited  basal 
growth.     The  thallus  does  not  yet  show  this  important 

165 


THE    WONDERS    OF    LIFE 

morphological  division.  There  are,  however,  exceptions 
in  both  groups  of  the  metaphyta.  The  large  and  highly- 
developed  fucoidea  among  the  algae  exhibit  similar  differ- 
entiations of  organs  to  those  we  distinguish  as  stalk  and 
leaves  in  the  higher  cormophyta.  On  the  other  hand, 
they  are  wanting  in  the  lower  liverworts,  which  form  a 
thallus  like  many  of  the  algae;  thus,  for  instance,  the 
liverwort  riccia  fluitans  is  just  like  the  brown  alga 
dictyota  dichotoma.  Other  primitive  livei^worts  (such 
as  the  antkoceros)  have  also  a  very  simple  thallus;  but 
most  of  them  have  a  separation  of  the  thallus  into  an 
axial  organ  (stalk)  and  several  lateral  organs  (leaves). 
In  the  distribution  of  labor  among  the  leaves  there 
then  emerge  the  differences  between  the  lower  leaves, 
foliage  leaves,  higher  leaves,  and  flower  leaves.  A  sim- 
ple poppy-plant  (papaver)  or  a  single-flowered  gentiana 
ciliata,  which  has  only  one  bloom  at  the  top  of  its 
branchless  stalk,  is  a  good  example  of  a  highly  developed 
culmus. 

To  the  plant-sprout  corresponds  in  the  animal  world 
the  person.  All  the  tissue-animals  pass  in  the  course  of 
their  embryonic  development  through  the  important 
stage  of  the  gastrida,  or  "cup-shaped  embryo."  The 
whole  body  of  the  tissue-animal  at  this  stage  forms  at 
first  a  simple  gut-sac  or  gastric  sac  (the  primitive  gut), 
the  cavity  of  which  opens  outward  by  a  primitive 
mouth.  The  thin  wall  of  the  sac  is  formed  by  two  super- 
imposed layers  of  cells,  the  two  primary  germinal  layers. 
This  gastrula  is  the  simplest  form  of  the  "person,"  and 
the  two  germinal  layers  are  its  sole  organs. 

The  diverse  animal  forms  which  develop  along  differ- 
ent lines  from  this  common  embryonic  form  of  the  gas- 
trula may  be  grouped  into  two  sub-kingdoms,  the  lower 
(ca'lcnteria)  and  the  upper  (ccelomaria)  animals.  The 
former  correspond  in  the  simplicity  of  their  structure  in 
many  respects  to  the  thallophyta,  and  the  latter  to  the 

i66 


UNITIES    OF    LIFE 

cormophyta.  Of  the  four  stems  of  the  coelenteria  (which 
have  only  a  ventral  opening  and  no  gut-cavity)  the 
gastrasads  remain  at  the  gastrula  stage,  and  the  sponges 
are  formed  by  multiplication  of  the  same  stems  of 
gastraeads.  On  the  other  hand,  the  cnidaria  develop 
into  higher  radial  (star-shaped)  persons,  and  the  platodes 
into  lower  bilateral  persons.  From  the  latter  are  derived 
the  worms  {vcrnialia),  the  common  stem-groups  of  the 
five  higher  animal  stems,  the  unarticulated  moUusks, 
echinoderms,  and  tunicates,  and  the  limb-forming  artic- 
ulates and  vertebrates. 

A  large  part  of  the  physiological  advantages  and  mor- 
phological perfection  which  the  higher  histona  have,  as 
contrasted  with  the  lower,  may  be  traced  to  the  circum- 
stance that  the  tissue-forming  organism  articulates — that 
is  to  say,  divides  on  its  long  axis  into  several  sections. 
With  this  multiplication  of  groups  of  organs  there  goes, 
as  a  rule,  a  more  or  less  extensive  division  of  work  among 
them,  a  leading  factor  of  higher  development.  In  this 
point  also  we  see  the  biogenetic  parallelism  between  the 
two  great  groups  of  the  tissue-plants  and  tissue-animals. 

In  the  kingdom  of  the  tissue-plants  the  articulated 
cormophyta  rise  high  above  the  unarticulated  thal- 
lophyta.  While  the  articulation  of  the  stem  of  the 
former  proceeds  and  leaves  are  developed  at  the  knots 
{nodi)  between  each  two  sections  of  the  stalk,  far  greater 
play  is  offered  to  polymorphic  differentiation  than  in  the 
thallophyta,  which  are  generally  without  this  meta- 
merism. The  formation  of  the  bloom  in  the  flowering 
plants  or  phanerogams  consists  in  a  sexual  division  of 
labor  among  the  thickly  gathered  leaves  in  a  short 
section  of  a  stem. 

To  the  two  groups  of  unarticulated  and  articulated 
sprouts  in  the  kingdom  of  the  tissue-plants  correspond, 
in  many  respects,  the  two  sections  of  the  tissue-animals, 
the  unarticulated  and  the  articulate.     The  two  stems  of 

167 


THE    WONDERS    OF    LIFE 

the  articulates  and  vertebrates  rise  above  all  the  other 
metazoa  by  the  perfection  of  their  organism  and  the 
variety  of  their  functions.  In  the  articulates  the  meta- 
merism is  chiefly  external — an  articulation  of  the  body 
wall.  In  the  vertebrates  it  mainly  affects  the  internal 
organs,  the  skeleton,  and  the  muscular  system.  The 
vertebration  (articulation)  of  the  vertebrates  is  not  out- 
wardly visible  like  that  of  the  articulates.  In  both  stems 
the  articulation  is  similar  in  the  lower  and  upper  forms, 
as  we  find  in  the  annelids  and  myriapods,  the  acrania  and 
cyclostoma.  On  the  other  hand,  the  higher  the  organi- 
zation the  greater  is  the  unlikeness  of  the  members  or 
articulated  parts,  as  in  the  arachnida  and  insects,  the 
amphibia  and  amniotes.  The  same  antithesis  is  found 
in  the  lower  and  higher  Crustacea.  This  metamerism 
of  the  higher  metazoa  is  of  a  motor  character,  having 
been  acquired  through  the  manner  of  movement  of  the 
lengthened  body;  but  we  find  in  some  groups  of  the 
lower,  and  usually  unarticulated,  metazoa  a  propagative 
metamerism,  determined  by  budding  at  the  end;  such  is 
the  strobilation  of  the  chain-worms  and  the  scyphostoma 
polyps.  The  individual  metamera  (parts)  that  are 
released  from  the  end  of  the  chain  in  these  cases  im- 
mediately show  their  individuality.  This  is  also  the 
case  with  many  of  the  annelids,  in  which  every  member 
that  is  separated  has  the  power  to  reproduce  the  whole 
chain  of  metamera. 

The  third  and  highest  stage  of  individuality  to  which 
the  multicellular  organism  attains  is  the  stock  or  colony 
{cormiis).  It  is  usually  formed  by  a  permanent  associa- 
tion of  histonals  that  are  produced  by  cleavage  (imper- 
fect segmentation  or  budding)  from  one  histonal  indi- 
vidual. The  great  majority  of  the  metaphyta  form 
complex  plants  in  this  sense.  But  among  the  metazoa 
we  find  this  form  of  individuality  only  in  the  lower  (and 
generally  stationary)  stages  of  development.    Here  also 

i68 


UNITIES    OF    LIFE 

there  is  a  striking  parallelism  of  development  between 
the  two  chief  groups  of  the  histona.  At  the  lower  stages 
of  stock-formation  there  is  equality  of  the  social  histonals. 
But  in  the  higher  grades  they  become  unequally  develop- 
ed in  the  division  of  labor;  and  the  greater  the  differences 
between  them  become,  the  greater  is  the  centralization  of 
the  whole  stock  (as  in  the  case  of  the  siphonophora). 
We  may  therefore  distinguish  two  principal  forms  of 
stocks — the  homonomous  and  heteronomous,  the  one 
without,  and  the  other  with,  division  of  labor  among 
the  histonals. 

The  history  of  civilization  teaches  us  that  its  gradual 
evolution  is  bound  up  with  three  different  processes: 
(i)  Association  of  individuals  in  a  community;  (2) 
division  of  labor  (ergonomy)  among  the  social  elements, 
and  a  consequent  differentiation  of  structure  (poly- 
morphism); (3)  centralization  or  integration  of  the 
unified  whole,  or  rigid  organization  of  the  community. 
The  same  fundamental  laws  of  sociology  hold  good  for 
association  throughout  the  entire  organic  world;  and 
also  for  the  gradual  evolution  of  the  several  organs  out 
of  the  tissues  and  cell-communities.  The  formation 
of  human  societies  is  directly  connected  with  the 
gregariousness  of  the  nearest  related  mammals.  The 
herds  of  apes  and  ungulates,  the  packs  of  wolves,  the 
flocks  of  birds,  often  controlled  by  a  single  leader, 
exhibit  various  stages  of  social  formation;  as  also  the 
swarms  of  the  higher  articulates  (insects,  Crustacea), 
especially  communities  of  ants  and  termites,  swarms  of 
bees,  etc.  These  organized  communities  of  free  individ- 
uals are  distinguished  from  the  stationary  colonies  ot 
the  lower  animals  chiefly  by  the  circumstance  that  the 
social  elements  are  not  bodily  connected,  but  held 
together  by  the  ideal  link  of  common  interest. 


VIII 

FORMS  OF  LIFE 

Morphology  —  Laws  of  symmetry  —  Fundamental  forms  of 
animals  and  plants — Fundamental  forms  of  protists  and 
histona — Four  chief  classes  of  fundamental  forms:  (i)  Cen- 
trostigma :  vesicles  (smooth  vesicle  and  tabular  vesicle) ; 
(2)  Centraxonia:  typical  forms  with  central  axis — Uniaxial 
(monaxonia,  equipolar  and  un-equipolar) — Transverse-axial 
(stauraxonia,  double-pyramidal  and  pyramidal) ;  (3)  Cen- 
troplana:  fundamental  forms  with  central  plane — Bilateral 
symmetry — Bilateral-radial  and  bilateral-symmetrical  fun- 
damental forms — Asymmetrical  fundamental  forms;  (4) 
Anaxonia:  irregular  fundamental  forms — Causes  of  form- 
construction — Fundamental  forms  of  monera,  protists,  and 
histona — Fundamental  form  and  mode  of  life — Beauty  of 
natural  forms — /Esthetics  of  organic  forms — Art  forms  in 
nature. 

THE  infinite  variety  of  forms  which  we  observe  in  the 
realm  of  organic  life  not  only  delight  our  senses  with 
their  beauty  and  diversity,  but  also  excite  our  curiosity, 
in  suggesting  the  problem  of  their  origin  and  connection. 
While  the  aesthetic  study  of  the  forms  of  life  provides 
inexhaustible  material  for  the  plastic  arts,  the  scientific 
study  of  their  relations,  their  structures,  their  origin  and 
evolution,  forms  a  special  branch  of  biology,  the  science 
of  forms  or  morphology.  I  expounded  the  principles  of 
^this  science  in  my  General  Morphology  thirty-eight  years 
ago.  They  are  so  remote  from  the  ordinary  curriculum 
of  education,  and  are  so  difficult  to  explain  without  the 
aid  of  numerous  illustrations,  that  I  cannot  think  of 

170 


FORMS    OF    LIFE 

going  fully  into  them  here.  In  the  present  chapter  I 
will  only  briefly  describe  those  features  of  living  things 
which  relate  to  the  difficult  question  of  their  ideal  funda- 
mental forms,  the  laws  of  their  symmetry,  and  their  rela- 
tion to  crystal -formation.  I  have  treated  these  intricate 
questions  somewhat  fully  in  the  last  (eleventh)  part  of 
Art-forms  in  Nature.  The  hundred  plates  contained  in 
this  work  may  serve  as  illustrations  of  morphological 
relations.  In  the  following  pages  the  respective  plates 
are  indicated  by  the  letters  A-f,  with  the  number  of 
each. 

The  unity  of  the  organic  structure,  which  expresses 
itself  everywhere  in  the  fundamental  features  of  living 
things  and  in  the  chemical  composition  and  constructive 
power  of  their  plasm,  is  also  seen  in  the  laws  of  symmetry 
in  their  typical  forms.  The  infinite  variety  of  the 
species  may,  both  in  the  animal  and  plant  worlds,  be 
reduced  to  a  few  principal  groups  or  classes  of  funda- 
mental forms,  and  these  show  no  difference  in  the 
two  kingdoms  (cf.  plate  6).  The  lily  has  the  same 
regular  typical  form  as  the  hexaradial  coral  or  anemone 
(A-f,  9,  49),  and  the  bilateral-radial  form  is  the  same  in 
the  violet  and  the  sea-urchin  (clypeaster,  A-f,  30).  The 
dorsiventral  or  bilateral-symmetrical  form  of  most  green 
leaves  is  repeated  in  the  frame  of  most  of  the  higher 
animals  (the  coelomaria) ;  the  distinction  of  right  and 
left  determines  in  each  the  characteristic  antithesis  of 
back  and  belly. 

The  distinction  between  protists  and  histons  is  much 
more  important  than  the  familiar  division  of  organisms 
into  plants  and  animals,  in  respect  of  their  fundamental 
forms  and  their  configuration.  For  the  protists,  the 
unicellular  organisms  (without  tissue)  exhibit  a  much 
greater  freedom  and  variety  in  the  development  of  their 
fundamental  forms  than  the  histons,  the  multicellular 
tissue-forming  organisms.     In   the   protists   (both  pro- 

171 


THE    WONDERS    OF    LIFE 

tophyta  and  protozoa)  the  constructive  force  of  the 
elementary  organism,  the  individual  cell,  determines  the 
symmetry  of  the  typical  form  and  the  special  form  of  its 
supplementation;  but  in  the  histons  (both  metaphyta 
and  metazoa)  it  is  the  plasticity  of  the  tissue,  made  up  of 
a  number  of  socially  combined  cells,  that  determines  this. 
On  the  ground  of  this  tectological  distinction  we  may 
divide  the  whole  organic  world  into  four  kingdoms  (or 
sub-kingdoms),  as  the  morphological  system  in  the 
seventh  table  shows. 

In  respect  of  the  general  science  of  fundamental 
forms  (promorphology),  the  most  interesting  and  varied 
group  of  living  things  is  the  class  of  the  radiolaria.  All 
the  various  fundamental  forms  that  can  be  distinguished 
and  defined  mathematically  are  found  realized  in  the 
graceful  flinty  skeletons  of  these  unicellular  sea-dwelling 
protozoa.  I  have  distinguished  more  than  four  thou- 
sand forms  of  them,  and  illustrated  by  one  hundred  and 
forty  plates,  in  my  monograph  on  the  Challenger  radio- 
laria [translated]. 

Only  a  very  few  organic  forms  seem  to  be  quite 
irregular,  without  any  trace  of  symmetry,  or  constantly 
changing  their  formless  shape,  as  we  find,  for  instance, 
in  the  amoebae  and  the  similar  amoeboid  cells  of  the 
Plasmodia.  The  great  majority  of  organic  bodies  show 
a  certain  regularity  both  in  their  outer  configuration  and 
the  construction  of  their  various  parts,  which  we  may 
call  "symmetry"  in  the  wider  sense  of  the  word.  The 
regularity  of  this  symmetrical  construction  often  ex- 
presses itself  at  first  sight  in  the  arrangement  side  by 
side  of  similar  parts  in  a  certain  number  and  of  a  certain 
size,  and  in  the  possibility  of  distinguishing  certain  ideal 
axes  and  planes  cutting  each  other  at  measurable  angles. 
In  this  respect  many  organic  forms  are  like  inorganic 
crystals.  The  important  branch  of  mineralogy  that 
describes    these    crystalline    forms,    and    gives    therr^ 

173 


FORMS    OF    LIFE 

mathematical  formuke,  is  called  crystallography.  There 
is  a  parallel  branch  of  the  science  of  biological  forms, 
promorphology,  which  has  been  greatly  neglected. 
These  two  branches  of  investigation  have  the  common 
aim  of  detecting  an  ideal  law  of  symmetry  in  the  bodies 
they  deal  with  and  expressing  this  in  a  definite  mathe- 
matical formula. 

The  number  of  ideal  fundamental  forms,  to  which  we  / 
may  reduce  the  symmetries  of  the  innumerable  living 
organisms,  is  comparatively  small.  Formerly  it  was 
thought  sufficient  to  distinguish  two  or  three  chief 
groups:  (i)  radial  (or  actinomorphic)  types,  (2)  bilateral 
(or  zygomorphic)  types,  and  (3)  irregular  (or  amorphic) 
types.  But  when  we  study  the  distinctive  marks  and 
differences  of  these  types  more  closely,  and  take  due 
account  of  the  relations  of  the  ideal  axes  and  their  poles, 
we  are  led  to  distinguish  the  nine  groups  or  types  which 
are  found  in  the  sixth  table.  In  this  promorphological 
system  the  determining  factor  is  the  disposition  of  the 
parts  to  the  natural  middle  of  the  body.  On  this  basis 
we  make  a  first  distinction  into  four  classes  or  types: 
(i)  the  centrostigma  have  a  point  as  the  natural  middle 
of  the  body;  (2)  the  centraxonia  a  straight  line  (axis); 
(3)  the  centroplana  a  plane  (median  plane);  and  (4)  the 
centraporia  (acentra  or  anaxonia),  the  wholly  irregular 
forms,  have  no  distinguishable  middle  or  symmetry.  , 

I.  Centrostigmatic  Types. — The  natural  middle  of  the  \ 
body  is  a  mathematical  point.  Properly  speaking,  only  one 
form  is  of  this  type,  and  that  is  the  most  regular  of  all, 
the  sphere  or  ball.  We  may,  however,  distinguish  two  sub- 
classes, the  smooth  sphere  and  the  flattened  sphere.  The 
smooth  sphere  {holospJia'ra)  is  a  mathematically  pure  sphere, 
in  which  all  points  at  the  surface  are  equally  distant  from  the 
centre,  and  all  axes  drawn  through  the  centre  are  of  equal 
length.  We  find  this  realized  in  its  purity  in  the  ovum  of 
many  animals  (for  instance,  that  of  man  and  the  mammals) 
and  the  pollen  cells  of  many  plants;  also  cells  that  develop  freely 

173 


r 


THE    WONDERS    OF    LIFE 

floating  in  a  liquid,  the  simplest  forms  of  the  radiolaria  (actissa), 
the  spherical  coenobia  of  the  volvocina  and  catallacta,  and  the 
corresponding  pure  embryonic  form  of  the  hlastula.  The 
smooth  sphere  is  particularly  important,  because  it  is  the  only 
absolutely  regular  type,  the  sole  form  with  a  perfectly  stable 
equilibrium,  and  at  the  same  time  the  sole  organic  form  which 
is  susceptible  of  direct  physical  explanation.  Inorganic  fluids 
(drops  of  quicksilver,  water,  etc.)  similarly  assume  the  purely 
spherical  form,  as  drops  of  oil  do,  for  instance,  when  put  in  a 
watery  fluid  of  the  same  specific  weight  (as  a  mixture  of  alcohol 
and  water). 

The  flattened  sphere,  or  facetted  sphere  {platnosphcBra) ,  is 
known  as  an  endospherical  polyhedron;  that  is  to  say,  a  many- 
surfaced  body,  all  the  corners  of  which  fall  in  the  surface  of  a 
sphere.  The  axes  or  the  diameters,  which  are  drawn  through 
the  angles  and  the  centre,  are  all  unequal,  and  larger  than 
all  other  axes  (drawn  through  the  facets).  These  facetted 
spheres  are  frequently  found  in  the  globular  silicious  skeletons 
of  many  of  the  radiolaria;  the  globular  central  capsule  of  many 
spheroidea  is  enclosed  in  a  concentric  gelatine  envelope,  on  the 
round  surface  of  which  we  find  a  net-work  of  fine  silicious  threads. 
The  meshes  of  this  net  are  sometimes  regular  (generally  trian- 
gular or  hexagonal),  sometimes  irregular;  frequently  starlike 
silicious  needles  rise  from  the  knots  of  the  net- work  (A-f,  i, 
51,  91).  The  pollen  bodies  in  the  flower-dust  of  many  flowering 
plants  also  often  assume  the  form  of  facetted  spheres. 

II.  Centraxonia  Types. — The  natural  middle  of  the  body 
is  a  straight  line,  the  principal  axis.  This  large  group  of  funda- 
mental forms  consists  of  two  classes,  according  as  each  axis  is 
the  sole  fixed  ideal  axis  of  the  body,  or  other  fixed  transverse 
axes  may  also  be  distinguished,  cutting  the  first  at  right  angles. 
We  call  the  former  uniaxial  {monaxonia) ,  and  the  latter  trans- 
verse-axial {staiiraxonia) .  The  horizontal  section  (vertically 
to  the  chief  axis)  is  round  in  the  uniaxials  and  polygonal  in  the 
transverse-axial. 

In  the  monaxonia  the  form  is  determined  by  a  single  fixed 
axis,  the  principal  axis;  the  two  poles  may  be  either  equal 
{isopold)  or  unequal  {allopola).  To  the  isopola  belong  the 
familiar  simple  forms  which  are  distinguished  in  geometry  as 
spheroids,  biconvex,  ellipsoids,  double  cones,  cylinders,  etc.  A 
horizontal  section,  passing  through  the  middle  of  the  vertical 
chief  axis,  divides  the  body  into  two  corresponding  halves. 
On  the  other  hand,  many  of  the  parts  are  unequal  in  size  and 
shape  in  the  allopola.     The  upper  pole  or  vertex  differs  from 

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FORMS    OF    LIFE 

the  basal  pole  or  ground  surface;  as  we  find  in  the  oval  form, 
the  planoconvex  lens,  the  hemisphere,  the  cone,  etc.  Both 
sub-classes  of  the  monaxonia,  the  allopola  (conoidal)  and  the 
isopola  (spheroidal) ,  are  found  realized  frequently  in  organic 
forms,  both  in  the  tissue -cells  of  the  histona  and  the  inde- 
pendently living  protists  (A-f,  4,  84). 

In  the  stauraxonia  the  vertical  imaginary  principal  axis  is 
cut  by  two  or  more  horizontal  cross-axes  or  radial-axes.  This 
is  the  case  in  the  forms  which  were  formerly  generally  classed  as 
regular  or  radial.  Here  also,  as  with  the  inonaxonia,  we  may 
distinguish  two  sub-classes,  isopola  and  allopola,  according  as 
the  poles  of  the  principal  axis  are  eaual  or  unequal. 

Of  the  stauraxonia  isopola  we  have,  for  instance,  the  double 
pyramids,  one  of  the  simplest  forms  of  the  octahedron.  This 
form  is  exhibited  very  typically  by  most  of  the  acantharia,  the 
radiolaria  in  which  twenty  radial  needles  (consisting  of  silicated 
chalk)  shoot  out  from  the  centre  of  the  vertical  chief  axis. 
These  twenty  rays  are  (if  we  imagine  the  figure  of  the  earth  with 
its  vertical  axis)  distributed  in  fiv^e  horizontal  zones,  with  four 
needles  each,  in  this  wise:  two  pairs  cross  at  right  angles  in  the 
equatorial  zone,  but  on  each  side  (in  north  and  south  hemi- 
spheres) the  points  of  four  needles  fall  in  the  tropical  zone,  and 
the  points  of  four  polar  needles  in  the  polar  circles;  twelve 
needles  (the  four  equatorial  and  eight  polar)  lie  in  two  meridian 
planes  that  are  vertical  to  each  other;  and  the  eight  tropical 
needles  lie  in  two  other  meridian  planes  which  cross  the  former 
at  an  angle  of  forty-five  degrees.  In  most  of  the  acantharia  (the 
radial  acanthometra  and  the  mailed  acanthophracta) — there 
are  few  exceptions — this  remarkable  structural  law  of  twenty 
radial  needles  is  faithfully  maintained  by  heredity.  Its  origin 
is  explained  by  adaptation  to  a  regular  attitude  which  the 
sea-dwelling  unicellular  body  assumes  in  a  certain  stage  of 
equilibrium  (A-f,  21,  41).  If  the  points  of  the  real  needles  are 
connected  by  imaginary  lines,  we  get  a  polyhedrical  body,  which 
may  be  reduced  to  the  form  of  a  regular  double  pyramid. 
This  typical  form  of  the  equipolar  stauraxonia  is  also  found  in 
other  protists  with  a  plastic  skeleton,  as  in  many  diatomes  and 
desmidiacea  (A-f,  24").  It  is  more  rarely  found  embodied  in  the 
tissue-cells  of  the  histona. 

Unequipolar  stauraxonia  are  the  pyramids,  a  fundamental 
form  that  plays  an  important  part  in  the  configuration  of 
organic  bodies.  They  were  formerly  described  as  regular  or 
fundamental  forms.  Such  are  the  regular  blooms  of  flowering 
plants,  the  regular  echinoderms,  medusae,  corals,  etc.     Wc  may 

175 


THE    WONDERS    OF    LIFE 

distinguish  several  groups  of  them  according  to  the  number 
of  the  horizontal  transverse  axes  that  cut  the  vertical  main 
axis  in  the  middle. 

Two  totally  different  divisions  of  the  pyramidal  types  are  the 
regular  and  the  amphithecta  pyramids.  In  the  regular  pyra- 
mids the  transverse  axes  are  equal,  and  the  ground-surface  (or 
base)  is  a  regular  polygon,  as  in  the  three- rayed  blooms  of  the 
iris  and  crocus,  the  four-rayed  medusas  (A-f,  i6,  28,  47,  48,  etc.), 
the  five-rayed  "regular  echinoderms,"  most  of  the  star-fish, 
sea-urchins,  etc.  (A-f,  10,  40,  60),  and  the  six-rayed  "regular 
corals"  (A-f,  9,  69). 

The  amphithecta  (or  two-edged)  pyramids,  a  special  group  of 
pyramidal  types,  are  characterized  by  having  as  their  basis  a 
rhombus  instead  of  a  regular  polygon.  We  may,  therefore, 
draw  two  imaginary  transverse  axes,  vertical  to  each  other, 
through  the  ground-surface,  both  equipolar,  but  of  unequal 
length.  One  of  the  two  may  be  called  the  sagittal  axis  (with 
dorsal  and  ventral  pole),  and  the  other  the  transverse  axis  (with 
right  and  left  pole) ;  but  the  distinction  is  arbitrary,  as  the  two 
are  equipolar.  In  this  lies  the  chief  difference  from  the  cen- 
troplane  and  dorsi ventral  forms,  in  which  only  the  lateral  axis 
is  equipolar,  the  sagittal  axis  being  unequipolar.  We  find  the 
bisected  pyramid  in  a  very  perfect  form  in  the  class  of  the 
ctenophora  (or  comb-medusae,  A-f,  27),  where  it  is  quite  general. 
The  striking  typical  form  of  these  pelagic  cnidaria  is  sometimes 
called  biradial,  sometimes  four- rayed  and  bilateral,  and  some- 
times eight-rayed-symmetrical.  Closer  study  shows  it  to  be  a 
rhombus-pyramid.  The  originally  four-rayed  type,  which  it 
inherited  from  craspedote  medusfe,  has  become  bilateral  by  the 
development  of  different  organs  to  the  right  and  left  from  those 
before  and  behind. 

Similar  rhombo-pyramidal  forms  to  those  of  the  ctenophora 
are  also  found  in  some  of  the  medusae  and  siphonophora,  many 
of  the  corals  and  other  cnidaria,  and  many  flowers.  The  name 
"two-edged"  which  is  given  to  this  special  type  is  taken  from 
the  ancient  two-edged  sword.  Its  chief  axis  is  unequipolar,  the 
handle  being  at  the  basic  pole  and  the  point  at  the  verticel  pole; 
but  the  two  edges  left  and  right  are  equal  (poles  of  the  lateral 
axis),  and  also  the  two  broad  surfaces  (dorsal  and  ventral, 
joined  by  the  sagittal  axis). 

III.  Centroplane  Types. — The  natural  middle  of  the  body 
is  a  plane,  the  median  or  chief  plane  {planum  medmmim  or 
sagittale) ;  it  divides  the  bilateral  body  into  two  symmetrical 
halves,   the  right   and  the   left.     With   this  is   associated   the 

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FORMS    OF    LIFE 

characteristic  antithesis  of  back  (dorsum)  and  belly  (venter) ; 
hence,  in  botany  this  type  (found,  for  instance,  in  most  green 
leaves)  is  called  the  dorsiventral,  and  in  zoology  the  bilateral 
in  the  narrower  sense.  One  characteristic  of  this  important  and 
wide-spread  type  is  the  relation  of  three  different  axes,  vertical 
to  each  other,  of  these  three  straight  axes  (enthynt)  two  are 
unequipolar  and  the  third  equipolar.  Hence,  the  centroplanes 
may  also  be  called  tri-axial  (triaxonia) .  In  most  of  the  higher 
animals  (as  in  our  own  frame)  the  longest  of  the  three  axes  is 
the  principal  one  (axon  principalis) ;  its  fore  pole  is  the  oral  or 
mouth  pole,  and  its  hinder  pole  is  the  aboral  or  caudal  (tail) 
pole.  The  shortest  of  the  three  enthyni  is,  in  our  body,  the 
sagittal  (arrow)  or  dorsiventral  axis;  its  upper  pole  is  at  the 
back  and  its  lower  pole  at  the  belly.  The  third  axis — the 
transverse  or  lateral  axis — is  equipolar,  one  pole  being  called 
the  right  and  the  other  the  left.  The  various  parts  which  make 
up  the  two  halves  of  the  body  have  relatively  the  same  dis- 
position in  each  half;  but  absolutely  speaking  (namely,  in 
relation  to  the  middle  plane)   they  are  oppositely  arranged. 

Further,  the  centroplane  or  bilateral  forms  are  also  charac- 
terized by  three  vertical  axes  which  may  be  drawn  through 
each  of  the  normal  axes.  The  first  of  these  normal  planes  is 
the  median  plane;  it  is  defined  by  the  chief  axis  and  the  sagittal 
axis,  and  divides  the  body  into  cwo  symmetrical  halves,  the 
right  and  left.  The  second  normal  plane  is  the  frontal  plane; 
this  passes  through  the  chief  axis  and  the  transverse  axis  (which 
is  parallel  to  the  frontal  surface  in  our  body),  and  divides  the 
dorsal  half  from  the  ventral  half.  The  third  normal  plane  is 
the  cingular  (waist)  plane;  this  is  defined  by  the  sagittal  and 
transverse  axes.  It  divides  the  head  half  (or  the  vertical  part) 
from  the  tail  half  (or  the  basal  part). 

The  name  "bilateral  symmetry,"  which  is  especially  applied 
to  the  centroplane  and  dorsiventral  types,  is  ambiguous,  as  I 
pointed  out  in  1866  in  an  exhaustive  analysis  and  criticism 
of  these  fundamental  forms  in  the  fourth  book  of  the  General 
Morphology.  It  is  used  in  five  different  senses.  For  our  present 
general  purpose  it  suffices  to  distinguish  two  orders  of  centro- 
plane types,  the  bilateral-radial  and  the  bilateral-symmetrical; 
in  the  former  the  radial  (pyramidal)  form  is  combined  with  the 
bilateral,  but  not  in  the  latter. 

The  bilateral-radial  type  comprises  those  forms  in  which  the 
radial  structure  is  combined  in  a  very  characteristic  fashion  with 
the  bilateral.  We  have  striking  examples  in  the  three-rayed 
flowers  of  the  orchids  (A-f,  74),  the  five-rayed  blooms  of  the 

177 


THE    WONDERS    OF    LIFE 

labiate  and  papilionaceous  flowers,  etc.,  in  the  plant  world: 
and  in  the  five-rayed  "irregular"  echinoderms,  the  bilateral 
sea-urchins  (spatangida,  clypeastrida,  A-f.  30)  in  the  animal 
world.  In  these  cases  the  bilateral  symmetry  is  recognizable  at 
the  first  glance,  as  is  also  the  radial  structure,  or  the  composition 
from  three  to  five  or  more  raylike  parts  (parainera),  which  are 
arranged  bilaterally  round  a  common  central  plane. 

The  bilateral-symmetrical  type  is  general  among  the  higher 
animals  which  move  about  freely.  The  body  consists  of  two 
antithetic  parts  {antitnera) ,  and  has  no  trace  of  radial  structure. 
In  the  free  moving,  creeping,  or  swimming  animals  (vertebrates, 
articulates,  mollusks,  annelids,  etc.)  the  ventral  side  is  under- 
neath, against  the  ground,  and  the  dorsal  side  upward.  This 
form  is  clearly  the  most  useful  and  practical  of  all  conceivable 
types  for  the  movement  of  the  body  in  a  definite  direction  and 
position.  The  burden  is  equally  distributed  between  the  two 
sides  (right  and  left) ;  the  head  (with  the  sense  organs,  the 
brain,  and  the  mouth)  faces  frontward  and  the  tail  behind. 
For  thousands  of  years  all  artificial  vehicles  (carts  on  land  and 
ships  in  water)  have  been  built  on  this  type.  Selection  has 
recognized  it  to  be  the  best  and  preserved  it,  while  it  has  dis- 
carded the  rest.  There  are,  however,  other  causes  that  have 
produced  the  predominance  of  this  type  in  green  leaves — the 
relation  to  the  supporting  stalk,  to  the  sun-light  that  falls  from 
above,  etc. 

Special  notice  must  be  taken  of  those  bilateral  forms 
which  were  originally  symmetrical  (by  heredity),  but 
have  subsequently  become  asymmetrical  (or  of  unequal 
halves),  by  adaptation  to  special  conditions  of  life.  The 
most  familiar  example  among  the  vertebrates  are  the 
flat-fishes  (plciironectides),  soles,  flounders,  turbots,  etc. 
These  high  and  narrow  and  flattened  boney-fishes  have 
a  perfect  bilateral  symmetry  when  young,  like  ordinary 
fishes.  Afterwards  they  form  the  habit  of  laying  on 
one  side  (right  or  left)  at  the  bottom  of  the  sea;  and  in 
consequence  the  upper  side,  exposed  to  the  light,  is  dark 
colored,  and  often  marked  with  a  design  (sometimes 
very  like  the  stony  floor  of  the  ocean  —  a  protective 
coloring),  while  the  side  the  flat-fish  lies  on  remains 
without   color.     But,   what  is  more  curious,   the   eye 

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FORMS    OF    LIFE 

from  the  under  side  travels  to  the  upper  side,  and  the 
two  eyes  Ue  together  on  one  side  (tlie  right  or  left); 
while  the  bones  of  the  skull  and  the  softer  parts  of  each 
side  of  the  head  grow  quite  crooked.  Naturally,  this 
ontogenetic  process,  in  which  a  striking  lack  of  symmetry 
succeeds  to  the  early  complete  symmetry  of  each  indi- 
vidual, can  only  be  explained  by  our  biogenetic  law;  it 
is  a  rapid  and  brief  recapitulation  (determined  by 
heredity)  of  the  long  and  slow  phyletic  process  which 
the  flat-fish  has  undergone  for  thousands  of  years  in  its 
ancestral  history  to  bring  about  its  gradual  modification. 
At  the  same  time,  this  interesting  metamorphosis  of  the 
pleuroncctidcs  gives  us  an  excellent  instance  of  the 
inheritance  of  acquired  characteristics,  as  a  consequence 
of  constant  oecological  habit.  It  is  quite  impossible  to 
explain  it  on  Weismann's  theory  of  the  germ-plasm. 

We  have  another  striking  example  among  the  inverte- 
brates in  the  snails  {gasteropoda).  The  great  majority 
of  these  moUusks  are  characterized  by  the  spiral  shape 
of  their  shells.  This  variously  shaped,  and  often 
prettily  colored  and  marked,  snail's  house  is  in  essence 
a  spirally  coiled  tube,  closed  at  the  upper  end  and 
open  at  the  lower  (or  mouth) :  the  moUusk  can  at  any 
moment  withdraw  into  its  tube.  The  comparative 
anatomy  and  ontogeny  of  the  snails  teach  us  that  this 
spiral  shell  came  originally  from  a  simple  discoid  or 
cylindrical  dorsal  covering  of  the  once  bilateral-symmet- 
rical moUusk,  by  the  two  sides  of  the  body  having  an 
unequal  growth.  The  cause  of  it  was  a  purely  me- 
chanical factor — the  sinking  of  the  growing  visceral 
sac,  covered  with  the  shell,  to  one  side;  one  part  of  the 
viscera  contained  in  it  (the  heart,  kidneys,  liver,  etc.) 
grew  more  stronglv  on  one  side  than  the  other  in  conse- 
quence of  this;  and  this  was  accompanied  by  consider- 
able displacement  and  modification  of  the  neighboring 
parts,  especially  the  gills.     In  most  snails  one  of  the 

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THE    WONDERS    OF    LIFE 

gills  and  kidneys  and  the  ventricle  of  the  heart  corre- 
sponding to  these  have  disappeared  altogether,  only 
those  of  the  opposite  side  remaining;  and  the  latter 
have  moved  from  the  right  side  to  the  left,  or  vice  versa. 
The  conspicuous  lack  of  symmetry  between  the  two 
halves  of  the  body  which  resulted  from  this  finds  ex- 
pression in  the  spiral  form  of  the  snail's  shell.  This  re- 
markable ontogenetic  metamorphosis  also  can  be  fully 
explained  by  a  corresponding  phylogenetic  process,  and 
affords  a  very  fine  instance  of  the  inheritance  of  acquired 
characters. 

There  are  also  many  examples  of  this  asymmetry  of 
bilateral  forms  in  the  plant  world,  such  as  the  green 
foliage-leaves  of  the  familiar  begonia  and  the  blooms  of 
canna. 

IV.  The  Centraporia. — Few  organic  forms  are  com- 
pletely irregular  and  without  axes,  as  usually  the  attrac- 
tion to  the  earth  (geotaxis)  or  to  the  nearest  object 
determines  the  special  direction  of  growth,  and  so  the 
formation  of  an  axis  in  some  direction  or  other.  Never- 
theless, we  may  instance  as  quite  irregular  the  soft  and 
ever-changing  plasma-bodies  of  many  rhizopods,  the 
amoebinae,  mycetozoa,  etc.  Most  of  the  sponges  also — 
which  we  regard  as  stocks  of  gastraeads — are  completely 
irregular  in  structure;  the  most  familiar  example  is  the 
common  bath-sponge. 

An  impartial  and  thorough  study  of  organic  forms  has 
convinced  me  that  their  actual,  infinitely  varied  con- 
figurations may  all  be  reduced  to  the  few  typical  forms 
I  have  described.  Comparative  anatomy  and  ontogeny 
further  teach  us  that  the  countless  modifying  processes 
which  have  led  to  the  appearance  of  the  various  species 
have  acted  by  adaptation  to  different  environments, 
habits,  and  customs,  and  give  us,  in  conjunction  with 
heredity,  a  physiological  explanation  of  this  morpho- 
logical transformation.     But  the  question  arises  as  to 

1 80 


FORMwS    OF    LIFE 

the  origin  of  these  few  geometrically  definable  types, 
and  the  cause  of  their  divergence. 

In  this  important  and  ditlicult  question  we  find  a  great 
variety  of  opinions  and  a  strong  leaning  to  dualistic  and 
mystic  theories.  Educated  laymen,  who  have  only  a 
partial  and  imperfect  acquaintance  with  the  biological 
facts,  think  that  they  are  justified  here  in  appealing  to  a 
supernatural  creation  of  forms.  They  contend  that  only 
a  wise  creator,  following  a  rational  and  conscious  design, 
could  produce  such  structures.  Even  distinguished  and 
informed  scientists  lean  in  this  matter  towards  mystic 
and  transcendental  ideas ;  they  believe  that  the  ordinary 
natural  forces  do  not  suffice  to  explain  these  phenomena, 
and  that  at  least  for  the  first  construction  of  these 
fundamental  types  we  must  postulate  a  deliberate 
creative  thought,  a  design,  or  some  such  teleological 
cause,  and  therefore  consciously  acting  final  causes. 
So  say  Nageli  and  Alexander  Braun. 

In  direct  opposition  to  this,  I  have  ever  maintained 
the  view  that  the  action  of  familiar  physical  forces — 
mechanical  efficient  causes — fully  suffices  to  explain  the 
origin  and  transformation  of  these  fundamental  types, 
as  well  as  for  all  other  biological  and  inorganic  processes. 
In  order  to  understand  this  monistic  position  thoroughly, 
and  to  meet  the  errors  of  duahsm,  we  must  bear  in  mind 
always  the  radical  processes  of  growth  which  control  all 
organic  and  inorganic  configuration,  and  also  the  long 
chain  of  advancing  stages  of  development,  which  lead  us 
from  the  simplest  protists,  the  monera,  to  the  most 
advanced  organisms. 

The  unicellular  organisms  exhibit  the  greatest  variety 
from  the  promorphological  point  of  view.  In  the  single 
class  of  the  radiolaria  we  find  all  imaginable  geometrical 
types  represented.  This  is  seen  in  a  glance  at  the  one 
hundred  and  forty  plates  on  which  I  have  depicted 
thousands  of  these  graceful  little  protozoa  in  my  mono- 

i8i 


THE    WONDERS    OF    LIFE 

graph  (Challenger  Report,  vol.  xviii.).  On  the  other 
hand,  the  monera,  at  the  lowest  stage  of  organic  life, 
the  structureless  organisms  without  organs  that  live 
on  the  very  frontier  of  the  inorganic  world,  are  very 
simple.  Especially  interesting  in  this  connection  are 
the  chromacea,  which  have  hitherto  been  so  unde- 
servedly and  so  incomprehensibly  neglected.  Among 
the  well-known  and  widely  distributed  chroococcacea, 
the  chroococcus,  coelosphaerium,  and  aphanocapsa  are 
quite  the  most  primitive  of  all  organisms  known  to  us 
— and  at  the  same  time  the  organisms  that  enable  us 
best  to  understand  the  origin  of  life  by  spontaneous 
generation  (archigony).  The  whole  organism  is  merely 
a  tiny,  bluish-green  globule  of  plasm,  without  any  struct- 
ure, or  only  surrounded  by  a  thin  membrane;  its  funda- 
mental form  is  the  simplest  of  all,  the  centraxial  smooth 
sphere.  Next  to  these  are  the  oscillaria  and  nostochina, 
social  chromacea,  which  have  the  appearance  of  thin, 
bluish-green  threads.  They  consist  of  simple  primitive 
(unnucleated)  cells  joined  to  each  other;  they  seem  often 
to  be  flattened  into  a  discoid  shape  as  a  result  of  close 
conjunction.  Many  protists  are  found  in  two  conditions, 
one  mobile  with  very  varied  and  changeable  forms,  and 
one  stationary  with  a  globular  shape.  But  when  the 
separate  living  cell  begins  to  form  a  firm  skeleton  or  pro- 
tective cover  for  itself,  it  may  assume  the  most  varied 
and  often  most  complicated  forms.  In  this  respect  the 
class  of  the  radiolaria  among  the  protozoa,  and  the  class 
of  the  diatomes  among  the  protophyta  (both  of  which 
have  flinty  shells),  surpass  all  the  other  groups  of  the 
diversified  realm  of  the  protists.  In  my  Art-forms  in 
Nature  I  have  given  a  selection  of  their  most  beautiful 
forms  (diatomes,  A-f,  4,  84;  radiolaria,  A-f,  i,  11,  21, 
22,  31,  41,  51,  61,  71,  95).  The  most  remarkable  and 
most  important  fact  about  them  is  that  the  artistic 
builders  of  these  wonderful  and  often  very  ingenious  and 

182 


FORMS    OF    LIFE 

intricate  flinty  structures  are  merely  the  plastidulcs  or 
micella,  the  molecular  and  microscopically  invisible  con- 
stituents of  the  soft  viscous  plasm  (sarcode). 

The  configuration  of  the  histona  differs  essentially 
from  that  of  the  protists,  since  in  the  case  of  the  latter 
the  simple  unicellular  body  produces  for  itself  alone  the 
whole  form  and  vital  action  of  the  organism,  while  in 
the  histona  this  is  done  by  the  cell  state,  or  the  social 
combination  of  a  number  of  different  cells,  which  make 
up  the  tissue  body.  Hence  the  ideal  type  which  we  can 
always  define  in  the  actual  histonal  form  has  quite  a 
different  significance  from  that  in  the  unicellular  pro- 
tists. In  the  latter  we  find  the  utmost  diversity  in  the 
configuration  of  the  independent  living  cells  and  the 
protective  cover  it  forms ;  among  the  histona  the  number 
of  fundamental  forms  is  limited.  It  is  true  that  the 
cells  themselves  which  make  up  the  tissues  may  exhibit 
a  great  variety  in  form  and  structure;  but  the  number 
of  the  different  tissues  which  they  make  up  is  small,  and 
so  is  the  number  of  ideal  types  exhibited  by  the  organism 
they  combine  to  form — the  sprout  (cnlmus)  in  the  plant 
kingdom  and  the  person  in  the  animal  kingdom.  The 
same  may  be  said  of  the  stock  (cormtis)  in  both  king- 
doms— that  is  to  say,  of  the  higher  individual  unity 
which  is  constituted  by  the  union  of  several  sprouts  or 
persons. 

The  two  classes  of  fundamental  forms  which  are  espe- 
cially found  in  the  plant  sprouts  or  the  animal  persons 
are  the  radial  and  bilateral.  The  one  is  determined  by 
the  stationary  life,  the  other  by  free  movement  in  a  cer- 
tain attitude  and  direction  (swimming  in  water  or  creep- 
ing on  the  ground).  Hence  we  find  the  radial  form  (as 
pyramidal)  predominant  in  the  blooms  and  fruits  of  the 
metaphyta,  and  the  persons  of  the  polyps,  corals,  and 
regular  echinoderms.  On  the  other  hand,  the  bilateral 
or  dorsiventral  form  preponderates  in  most  free-moving 

•83 


THE    WONDERS    OF    LIFE 

animals ;  though  it  is  also  found  in  many  flowers  (papil- 
ionaceous and  labial  flowers,  orchids,  and  others  that 
are  fertilized  by  insects).  Here  we  have  to  seek  the 
cause  of  the  bilateralism  in  different  features,  in  the  re- 
lations with  the  insects,  in  the  mode  of  their  fastening  to 
and  distribution  on  the  stalk  (for  the  green  foliage  leaves), 
and  so  on. 

The  complex  individuals  of  the  first  order,  the  stocks 
(cormi),  are  more  dependent  in  their  growth  on  the  spatial 
conditions  of  their  environment  than  the  sprouts  or  per- 
sons; hence  their  typical  form  is  generally  more  or  less 
irregular,  and  rarely  bilateral. 

The  interest  which  we  take  in  natural  and  artistic 
forms,  and  which  has  for  thousands  of  years  prompted 
men  to  reproduce  the  former  in  the  latter,  depends  for 
the  most  part,  if  not  altogether,  on  their  beauty — that  is 
to  say,  on  the  feeling  of  pleasure  we  experience  in  look- 
ing at  them.  The  causes  of  this  pleasure  and  joy  in 
the  beautiful  and  the  naturalness  of  its  development  are 
explained  in  aesthetics.  When  we  combine  this  science 
with  the  results  of  modern  cerebral  physiology,  we  may 
distinguish  two  classes  of  beauty — direct  and  indirect. 
In  direct  or  sensible  beauty  the  internal  sense-organs,  or 
the  aesthetic  neurona  or  sense-cells  of  the  brain,  are  im- 
mediately affected  with  pleasure.  But  in  indirect  or 
associational  beauty  these  impressions  are  combined 
with  an  excitement  of  the  phronetic  neurona  —  the 
rational  brain  —  cells  which  effect  presentation  and 
thought. 

Direct  or  sensible  beauty  (the  subject  of  sensual 
aesthetics)  is  the  direct  perception  of  agreeable  stimuli 
by  the  sense-organs.  We  may  distinguish  the  following 
stages  of  its  perfection:  i.  Simple  beauty  (the  subject 
of  primordial  aesthetics) ;  the  pleasure  is  evoked  by  the 
direct  sense-impression  of  a  simple  form  or  color.  Thus, 
for  instance,  a  wooden  sphere  makes  an  agreeable  im- 

184 


FORMS    OF    LIFE 

pression  as  compared  with  a  shapeless  piece  of  wood,  a 
crystal  as  compared  with  a  stone,  a  sky-blue  or  golden- 
yellow  spot  as  compared  with  a  greenish-blue  or  dull- 
yellow  one  (in  music  a  simple  pure  bell-tone  as  com- 
pared with  a  shrill  whistle).  2.  Rhythmic  beauty  (the 
subject  of  linear  aesthetics) ;  the  aesthetic  sensation  is 
caused  by  the  serial  repetition  of  some  simple  form — 
for  instance,  a  pearl  necklace,  a  chainlike  community 
of  monera  (nostoc)  or  of  cells  (diatomes,  A.-f,  84,  figs. 
7  and  9):  in  music  a  tasteful  series  of  simple  notes.  3. 
Actinal  beauty  (the  subject  of  radial  aesthetics);  the 
pleasure  is  excited  by  the  orderly  arrangement  of  three 
or  more  homogeneous  .simple  forms  about  a  common 
centre,  from  which  they  radiate;  for  instance,  a  regular 
cross  or  a  radiating  star,  the  three  counter-pieces  in  the 
iris-bloom,  the  four  paramera  in  the  body  of  the  medusa, 
the  five  radial-pieces  in  the  star-fish.  The  familiar  ex- 
perience of  the  kaleidoscope  shows  how  amply  the  simple 
radial  constellation  of  three  or  more  simple  figures  may 
delight  our  aesthetic  sense  (in  music  we  have  the  simple 
harmony  of  several  simultaneous  notes).  4.  Symmet- 
rical beauty  (the  subject  of  bilateral  aesthetics) ;  the 
pleasure  is  caused  by  the  relation  of  a  simple  object  to 
its  like,  the  mutual  completion  of  two  similar  halves  (the 
right  and  left  parts).  When  we  fold  a  piece  of  paper 
over  an  ink-stain  in  such  a  way  that  it  is  equally  im- 
pressed on  both  halves  of  the  fold,  we  get  a  symmetrical 
figure  which  makes  an  agreeable  impression  on  our  nat- 
ural sense  of  space  or  equilibrium. 

The  aesthetic  impressions  in  indirect  associational 
beauty  (the  subject  of  associative  or  symbolical  aesthet- 
ics) are  not  only  much  more  varied  and  complex  than 
those  we  have  described,  but  they  also  play  a  much  more 
important  part  in  the  life  of  man  and  the  higher  animals. 
The  anatomic  condition  for  this  higher  physiological 
function  is  the  elaborate  construction  of  the  brain  in  the 

i8s 


THE    WONDERS    OF    LIFE 

higher  animals  and  man,  and  particularly  the  develop- 
ment of  the  special  association-centres  (thought-centres, 
reason-sphere)  and  their  differentiation  from  the  inter- 
nal sense-centres.  In  this  millions  of  different  neurona 
or  psychic  cells  co-operate,  the  sensual  aestheta  acting 
in  conjunction  with  the  rational  phroneta,  and  thus,  by 
complex  associations  of  ideas,  much  higher  and  more 
valuable  functions  arise.  We  may  indicate  four  chief 
groups  of  this  associational  or  indirect  beauty.  5.  Bio- 
logical beauty  (the  subject  of  botanical  and  zoological 
aesthetics) :  the  various  forms  of  organisms  and  their 
organs  (for  instance,  a  flower,  a  butterfly)  excite  our 
aesthetic  interest  by  association  with  their  physiological 
significance,  their  movements,  their  bionomic  relations, 
their  practical  use,  and  so  on.  6.  Anthropistic  beauty 
(the  subject  of  anthropomorphic  aesthetics):  man,  as 
"the  measure  of  all  things,"  regards  his  own  organism 
as  the  chief  object  of  beauty,  either  morphologically 
considered  (beauty  of  the  whole  body  and  its  various 
organs — the  eyes,  mouth,  hair,  flesh-tint,  etc.),  or  physi- 
ologically (beauty  of  movements  or  positions),  or  psycho- 
logically (the  expression  of  the  emotions  in  the  physi- 
ognomy). As  man  transfers  to  the  objective  world  this 
personal  gratification  he  experiences  from  self -considera- 
tion, and  anthropomorphically  regards  other  beings  in 
the  light  of  them,  this  anthropistic  aesthetic  obtains  a 
far-reaching  significance.  7.  Sexual  beauty  (the  subject 
of  erotic  aesthetics) :  the  pleasure  is  caused  by  the  mutual 
attraction  of  the  sexes.  The  supreme  importance  of 
love  in  the  life  of  man  and  most  other  organisms,  the 
powerful  influence  of  the  passions,  the  sexual  selection 
that  is  associated  with  reproduction,  have  evoked  an 
infinite  number  of  aesthetic  creations  in  every  branch  of 
art  relating  to  the  antithesis  of  man  and  woman.  The 
special  pleasure  which  is  caused  by  the  bodily  and  mental 
affinities  of  the  sexes  can  be  traced  phylogenetically  to 

186 


FORMS    OF    LIFE 

the  cell-love  of  the  two  sexual  cells,  or  the  attraction  of 
the  sperm-cell  to  ovum.  8.  Landscape  beauty  (the  sub- 
ject of  regional  aesthetics) :  the  pleasure  which  is  caused 
by  the  sight  of  a  fine  landscape,  and  that  finds  satisfac- 
tion in  modern  landscape-painting,  is  more  comprehen- 
sive than  that  of  any  other  aesthetic  sensations.  In  point 
of  space  the  object  is  larger  and  richer  than  any  of  the 
individual  objects  in  nature  which  are  beautiful  and  in- 
teresting in  themselves.  The  varying  forms  of  the 
clouds  and  the  water,  the  outline  of  the  blue  mountains 
in  the  background,  the  woods  and  meadows  in  the  mid- 
dle-distance, and  the  living  figures  in  the  foreground, 
excite  in  the  mind  of  the  spectator  a  number  of  differ- 
ent impressions  which  are  woven  together  into  a  har- 
monious whole  by  a  most  elaborate  association  of  ideas. 
The  physiological  functions  of  the  nerve-cells  in  the  cor- 
tex which  effect  these  aesthetic  pleasures,  and  the  inter- 
action of  the  sensual  aestheta  with  the  rational  phroneta, 
are  among  the  most  perfect  achievements  of  organic 
life.  This  "regional  aesthetics,"  which  has  to  establish 
scientifically  the  laws  of  landscape  beauty,  is  much 
younger  than  the  other  branches  of  the  science  of  the 
beautiful.  It  is  very  remarkable  that  absolute  irregu- 
larity, the  absence  of  symmetry  and  mathematical  forms, 
is  the  first  condition  for  the  beauty  of  a  landscape  (as 
contrasted  with  architecture,  and  the  beauty  of  separate 
objects  in  nature).  Symmetrical  arrangement  of  things 
(such  as  a  double  row  of  poplars  or  houses)  or  radial 
figures  (a  flower-bed  or  artificial  wood)  do  not  please  the 
finer  taste  for  landscape;  they  seem  tedious. 

A  comparative  survey  of  these  eight  kinds  of  beauty 
in  natural  forms  discovers  a  connected  development, 
rising  from  the  simple  to  the  complex,  from  the  lower 
to  the  higher.  This  scale  corresponds  to  the  evolution 
of  the  sense  of  beauty  in  man,  ontogenetically  from  the 
child  to  the  adult,  phylogenetically  from  the  savage  to 

187 


THE    WONDERS    OF    LIFE 

the  civilized  man  and  the  art  critic.  The  stem-history 
of  man  and  his  organs,  which  explains  to  us  in  anthro- 
pogeny  the  gradual  rise  from  lower  to  higher  forms  by 
the  interaction  of  heredity  and  adaptation,  also  finds  an 
application  in  the  history  of  aesthetics  and  ornamenta- 
tion. It  teaches  us  how  feeling,  taste,  emotion,  and  art 
have  been  gradually  evolved.  On  the  other  hand,  we 
have  corresponding  to  this  evolutionary  series  the  scale 
of  the  typical  forms  which  lie  at  the  root  of  the  real 
forms  of  bodies  both  in  nature  and  art. 


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IX 

MONERA 

The  simplest  forms  of  life — Cell  theory  and  cell  dogma — Precellu- 
lar  organisms:  monera,  cytodes,  and  cells — Actual  monera 
— Chromacea  (cyanophyceae)  —  Chromatophora  —  Coenobia 
of  chromacea:  vital  phenomena — Bacteria — Relations  of 
the  bacteria  to  the  chromacea,  the  fungi,  and  the  pro- 
tozoa— Rhizomonera  (protamoeba,  protogenes,  protomyxa, 
bathybius) — Problematic  monera — Phytomonera  (plasmo- 
doma)  and  zoomonera  (plasmophaga) — Transition  between 
the  two  classes. 

IN  the  study  and  explanation  of  all  complex  phenom- 
ena the  first  thing  to  do  is  to  understand  the  simple 
parts,  the  manner  of  their  combination,  and  the  develop- 
ment of  the  compound  from  the  simple.  This  principle 
applies  generally  to  inorganic  objects,  such  as  minerals, 
artificially  constructed  machines,  etc.  It  is  also  of  gen- 
eral application  in  biological  work.  The  efforts  of  com- 
parative anatomy  are  directed  to  the  comprehension  of 
the  intricate  structure  of  the  higher  organisms  from  the 
rising  scale  of  organization  and  life  in  the  lower,  and 
the  origin  of  the  former  by  historical  development  from 
the  latter.  The  modern  science  of  the  cell  (cytology), 
which  has  in  a  short  time  attained  a  considerable  rank, 
pursues  a  method  in  opposition  to  this  principle.  The 
intricate  composition  of  the  unicellular  organism,  in 
many  of  the  higher  protists  (such  as  the  ciliata  and 
infusoria)  and  many  of  the  higher  tissue-cells  (such  as 
the  neurona)  has  led  to  the  erroneous  ascription  of  a 

190 


MONERA 

highly  complex  organization  to  the  cell  in  general.  One 
would  be  justified  in  saying  that  of  late  the  cell-theory 
has  established  itself  in  the  dangerous  and  misleading 
position  of  a  cell-dogma. 

The  modern  treatment  of  the  science,  as  we  find  it  in 
numbers  of  recent  works,  even  in  some  of  the  most  dis- 
tinguished manuals,  and  which  we  must  resent  on  ac- 
count of  its  dogmatism,  culminates  in  something  like  the 
following  theses: 

1.  The  nucleated  cell  is  the  general  elementary  or- 
ganism; all  living  things  are  either  unicellular,  or  made 
up  of  a  number  of  cells  and  tissues. 

2.  This  elementary  organism  consists  of  at  least  two 
different  organs  (or,  more  correctly,  organella),  the  in- 
ternal nucleus  and  the  outer  cell-body  (or  cytoplasm). 

3.  The  matter  in  each  of  these  cell-organs — the  caryo- 
plasm  of  the  nucleus  and  the  cytoplasm  of  the  body — is 
never  homogeneous  (or  consisting  of  a  chemical  substra- 
tum), but  always  "organized,"  or  made  up  of  several 
chemically  and  anatomically  different  elementary  con- 
stituents. 

4.  The  plasm  (or  protoplasm)  is,  therefore,  a  morpho- 
logical, not  a  chemical,  unity. 

5.  Every  cell  comes  (and  has  come)  only  from  a 
mother-cell,  and  every  nucleus  from  a  mother-nucleus 
{oninis  celliila  e  cellula — omnis  nucleus  e  niiclco). 

These  five  theses  of  the  modem  cell-dogma  are  by  no 
means  sound;  they  are  incompatible  with  the  theor^^  of 
evolution.  I  have,  therefore,  consistently  resisted  them 
for  thirty -eight  years,  and  consider  them  to  be  so  dan- 
gerous that  I  will  briefly  give  my  reasons.  First,  let 
us  clearly  understand  the  modern  definition  of  the  cell. 
It  is  now  generally  defined  (in  accordance  with  the 
second  thesis)  as  being  composed  of  two  essentially 
different  parts,  the  nucleus  and  the  cell-body,  and  it  is 
added   that  these   organella   differ  constantly   both   in 

191 


THE    WONDERS    OF    LIFE 

respect  of  chemistry,  morphology,  and  physiology.  If 
that  is  really  so,  the  cell  cannot  possibly  be  the  primitive 
organism;  if  it  were,  we  should  have  a  miracle  at  the 
beginning  of  organic  life  on  the  earth.  The  theory  of 
natural  evolution  clearly  and  distinctly  demands  that 
the  cell  (in  this  sense)  is  a  secondary  development  from 
a  simpler,  primary,  elementary  organism,  a  homogene- 
ous cytode.  There  are  still  living  to-day  very  simple 
protists  which  do  not  tally  with  this  definition,  and  which 
I  designated  monera  in  1866.  As  they  must  necessarily 
have  preceded  the  real  cells,  they  may  also  be  called 
"  precellular  organisms." 

The  earliest  organisms  to  live  on  the  earth,  with  which 
the  wonderful  drama  of  life  began,  can,  in  the  present 
condition  of  biological  science,  only  be  conceived  as 
homogeneous  particles  of  plasm — biogens  or  groups  of 
biogens,  in  which  there  was  not  yet  the  division  of 
nucleus  and  cell-body  which  characterizes  the  real  cell. 
I  gave  the  name  "  cytodes  "  to  these  unnucleated  cells  in 
1866,  and  joined  them  with  the  real  nucleated  cells  under 
the  general  head  of  "plastids."  I  also  endeavored  to 
prove  that  such  cytodes  still  exist  in  the  form  of  indepen- 
dent monera,  and  in  1870  I  described  in  my  Monograph 
on  the  Monera  a  number  of  protists  which  do  not  tally 
with  the  above  definition. 

Fifty  years  ago  I  made  the  first  careful  observations  of 
living  monera  {protama^ha  and  protogcnes),  and  described 
theminmy  General  Morphology  {vol.  i.,  pp.  133-5;  vol.ii., 
p.  xxii.)  as  structureless  organisms  without  organs  and 
the  real  beginnings  of  organic  life.  Soon  afterwards, 
during  a  stay  in  the  Canary  Islands,  I  succeeded  in 
following  the  continuous  life-history  of  a  related  organ- 
ism of  the  rhizopod  type,  which  behaved  like  a  very 
simple  mycetozoon,  but  differed  in  having  no  nucleus;  I 
have  reproduced  the  picture  of  it  in  the  first  plate  of  my 
History  of  Creation.     The  description  of  this  orange-red 

1Q2 


MONERA 

globule  of  plasm  {protomyxa  aurantiaca)  appeared  first 
in  my  Monograph  on  the  Moncra.  Most  of  the  organisms 
whicli  I  comprised  under  this  name  exhibited  the  same 
movements  as  true  rhizopods  (or  sarcodina).  It  was 
afterwards  proved  of  some  of  them  that  there  was  a 
nucleus  hidden  within  the  homogeneous  particle  of  plasm, 
and  that,  therefore,  they  must  be  regarded  as  real  cells. 
But  this  discovery  was  wrongly  extended  to  the  whole  of 
the  monera,  and  the  existence  of  unnucleated  organisms 
was  denied  altogether.  Nevertheless,  there  are  living 
to-day  several  kinds  of  these  organisms  without  organs, 
some  of  them  being  very  widely  distributed.  The  chief 
examples  are  the  chromacea  and  the  bacteria,  the  former 
with  vegetal  and  the  latter  with  animal  metabolism  (or 
the  former  plasmodomous  =  plasma-forming,  and  the 
latter  plasmophagous=:plasma-feeding).  On  the  ground 
of  this  important  chemical  difference,  I  distinguished  two 
principal  groups  of  the  monera  in  my  Systematic  Phy- 
togeny twenty  years  ago  —  the  phytomonera  and  the 
zoomonera,  the  former  being  unnucleated  protophyta 
and  the  latter  unnucleated  protozoa. 

Among  living  organisms  the  chromacea  are  certainly 
the  most  primitive  and  the  nearest  to  the  oldest  inhabi- 
tants of  the  earth.  Their  simplest  forms,  the  chroococ- 
cacea,  are  nothing  but  small  structureless  particles  of 
plasm,  growing  by  plasmodomism  (formation  of  plasm) 
and  multiplying  by  simple  cleavage  as  soon  as  their 
growth  passes  a  certain  limit  of  individual  size.  Many 
of  them  are  surrounded  by  a  thin  membrane  or  some- 
what thicker  gelatinous  covering,  and  this  circumstance 
had  prevented  me  for  some  time  from  counting  the 
chromacea  as  monera.  However,  I  became  convinced 
afterwards  that  the  formation  of  a  protective  cover  of 
this  kind  around  the  homogeneous  particle  of  plasm  may 
indeed  be  regarded  from  the  physiological  stand-point  as 
a  "purposive"  structure,  but  at  the  same  time  may  be 
13  193 


THE    WONDERS    OF    LIFE 

looked  upon,  from  the  purely  physical  stand-point,  as  a 
result  of  superficial  strain.  On  the  other  hand,  the 
physiological  character  of  these  plasmodomous  monera 
is  especially  important,  as  it  gives  us  the  simple  key 
to  the  solution  of  the  great  question  of  spontaneous 
generation  (or  archigony,  c/.  chapter  xv.). 

The  chromacea  are  to-day  found  in  every  part  of  the 
earth,  living  sometimes  in  fresh  water  and  sometimes 
in  the  sea.  Many  species  form  blue-green,  violet,  or 
reddish  deposits  on  rocks,  stones,  wood,  and  other 
objects.  In  these  thin  gelatinous  plates  millions  of 
small  homogeneous  cytodes  are  packed  close  together. 
Their  tint  is  due  to  a  peculiar  coloring  matter  (phyco- 
cyan),  which  is  chemically  connected  with  the  substance 
of  the  plasma-particle.  The  shade  of  this  color  differs 
a  good  deal  in  the  various  species  of  chromacea  (of 
which  more  than  eight  hundred  have  been  distinguished) ; 
in  the  native  species  it  is  generally  blue-green  or  sage- 
green,  sometimes  blue,  cyanine  blue,  or  violet.  Hence 
the  common  name  cyanophyceas  {i.e.,  blue  algae).  It  is 
incorrect,  for  two  reasons;  firstly,  because  only  a  part  of 
these  protophyta  are  blue,  and,  secondly,  because  they 
(as  simple,  primitive  plants  without  tissue)  must  be 
distinguished  from  the  real  algae  (phyceae),  which  are 
multicellular,  tissue-forming  plants.  Other  chromacea 
are  red,  orange,  or  yellow  in  color,  as  the  interesting 
trichodesmium  erythrcutim,  for  instance,  the  flaky  masses 
of  which,  gathering  in  enormous  quantities,  cause  at 
certain  times  the  yellow  or  red  coloring  of  the  sea-water 
in  the  tropics;  it  is  these  that  are  responsible  for  the 
name  "Red  Sea"  on  the  Arabian  and  "Yellow  Sea"  on 
the  Chinese  coast.  When  I  passed  the  equator  in  the 
Sunda  Straits  on  March  lo,  1901,  the  boat  sailed  through 
colossal  accumulations,  several  miles  in  width,  of 
this  trichodesmium.  The  yellow  or  reddish  surface  of 
the  water  looked  as  if  it  were  strewn  with  sawdust. 

194 


MONERA 

In  the  same  way,  the  surface  of  the  Arctic  Ocean  is  often 
colored  brown  or  reddish-brown  by  masses  of  the  brown 
procytclla  prhnordialis  (formerly  described  as  protococciis 
niarinus). 

It  is  clearly  quite  illogical  to  regard  the  chromacea  as 
a  class  or  family  of  the  algae,  as  is  still  done  in  most 
manuals  of  botany.  The  real  algae  —  excluding  the 
unicellular  diatomes  and  paulotomes,  which  belong  to 
the  protophyta — are  multicellular  plants  that  form  a 
thallus  or  bed  of  a  certain  form  and  characteristic  tissue. 
The  chromacea,  which  have  not  advanced  as  far  as  the 
real  nucleated  cell,  are  unnucleated  cytodes  of  a  lower 
and  earlier  stage  of  plant-life.  If  one  would  compare 
the  chromacea  with  algae  or  other  plants  at  all,  the 
comparison  cannot  be  with  their  constituent  cells,  but 
merely  with  the  chromatophora  or  chromatella,  which 
are  found  in  all  green  plant-cells,  and  form  part  of  their 
contents.  To  be  more  precise,  these  green  granules 
of  chlorophyll  must  be  regarded  as  organella  of  the 
plant-cell,  or  separated  plasma-formations  which  arise 
beside  the  nucleus  in  the  cytoplasm.  In  the  embryonic 
cells  of  the  germs  of  plants  and  in  their  vegetation 
points  the  chromatophora  are  as  yet  colorless,  and  are 
developed,  as  solid,  very  refractive,  globular,  or  roundish 
granules,  from  the  firm  layer  of  plasm  which  imme- 
diately surrounds  the  nucleus.  Afterwards  they  are 
converted,  by  a  chemical  process,  into  the  green  chloro- 
phyll granules  or  chloroplasts,  which  have  the  most 
important  function  in  the  plasmodomism  or  carbon- 
assimilation  of  the  plant. 

The  fact  that  the  green  chlorophyll  granules  grow 
independently  within  the  living  plant-cell  and  multiply 
by  segmentation  is  very  important  and  interesting.  The 
globular  chloroplasts  are  constricted  in  the  middle,  and 
split  into  two  equal  daughter-globules.  These  daughter- 
plastids  grow,  and  multiply  in  turn  in  the  same  way. 

195 


THE    WONDERS    OF    LIFE 

Hence  they  behave  within  the  plant-cell  just  like  the 
free-living  chromacea  in  the  water.  On  the  strength  of 
this  significant  comparison,  one  of  our  ablest  and  most 
open-minded  scientists,  Fritz  Muller-Desterro,  of  Brazil, 
pointed  out  in  1893  that  we  may  see  in  every  green 
vegetal  cell  a  symbiosis  between  plasmodomous  green 
and  plasmophagous  not  -  green  companions  {cf.  my 
Anthropogeny,  figs.  277  and  278,  and  in  the  text). 

Many  species  of  the  simplest  chromacea  live  as 
monobia  (individually).  When  the  tiny  plasma  globules 
have  split  into  two  equal  halves  by  simple  segmentation, 
they  separate,  and  live  their  lives  apart.  This  is  the 
case  with  the  common,  ubiquitous  chroococcus.  How- 
ever, most  species  live  in  common,  the  plasma  granules 
forming  more  or  less  thick  coenobia,  or  communities  or 
colonies  of  cells.  In  the  simplest  case  (aphanocapsa)  the 
social  cytodes  secrete  a  structureless  gelatinous  mass,  in 
which  numbers  of  blue-green  plasma  globules  are  irregu- 
larly distributed.  In  the  glceocapsa,  which  forms  a  thin 
blue-green  gelatinous  deposit  on  damp  walls  and  rocks, 
the  constituent  cytodes  cover  themselves  immediately 
after  cleavage  with  a  fresh  gelatinous  envelope,  and  these 
run  together  into  large  masses.  But  the  majority  of  the 
chromacea  form  firm,  threadlike  cell  communities  or 
chains  of  plastids  (catenal  coenobia.)  As  the  transverse 
cleavage  of  the  rapidly  multiplying  cytodes  always 
follows  the  same  direction,  and  the  new  daughter-cytodes 
remain  joined  at  the  cleavage  surfaces,  and  are  flattened 
into  discoid  shape,  we  get  stringlike  formations  or 
articulated  threads  of  considerable  length,  as  in  the 
oscillaria  and  nostochina.  When  a  number  of  these 
threads  are  joined  together  in  gelatinous  masses,  we 
often  get  large,  irregular,  jelly-like  bodies,  as  in  the 
common  " shooting  -  star  jellies"  (nostoc  communis). 
They  attain  the  size  of  a  plum. 

In  view  of  the  extreme  importance  which  I  attach  to 

196 


M  O  N  E  R  A 

the  chromacea  as  the  earUest  and  snnplest  of  all  or- 
ganisms, it  is  necessary  to  put  clearly  the  following  facts 
with  regard  to  .their  anatomic  structure  and  physio- 
logical activity: 

1.  The  organism  of  the  simplest  chromacea  is  not 
composed  of  different  organella  or  organs;  and  it  shows 
no  trace  of  purposive  construction  or  definite  archi- 
tecture. 

2.  The  homogeneous  tinted  plasma  granule  which 
makes  up  the  entire  organism  in  the  simplest  case 
(chroococcus)  exhibits  no  plasma  structure  (honeycomb, 
threads,  etc.)  whatever. 

3.  The  original  globular  form  of  the  plasma  particle 
is  the  simplest  of  all  fundamental  types,  and  is  also  that 
assumed  by  the  inorganic  body  (such  as  a  drop  of  rain) 
in  a  condition  of  stable  equilibrium. 

4.  The  formation  of  a  thin  membrane  at  the  surface  of 
the  structureless  plasma  granule  may  be  explained  as  a 
purely  physical  process — that  of  surface  strain. 

5.  The  gelatinous  envelope  which  is  secreted  by  many 
of  the  chromacea  is  also  formed  by  a  simple  physical 
(or  chemical)  process. 

6.  The  sole  essential  vital  function  that  is  common  to 
all  the  chromacea  is  self-maintenance,  and  growth  by 
means  of  their  vegetal  metabolism,  or  plasmodomism 
(  =  carbon  assimilation);  this  purely  chemical  process  is 
on  a  level  with  the  catalysis  of  inorganic  compounds 
(chapter  x.). 

7.  The  growth  of  the  cytodes,  in  virtue  of  their  con- 
tinuous plasmodomism,  is  on  a  level  with  the  physical 
process  of  crystal  growth. 

8.  The  reproduction  of  the  chromacea  by  simple 
cleavage  is  merely  the  continuation  of  this  simple  growth 
process,  when  it  passes  the  limit  of  individual  size. 

9.  All  the  other  vital  phenomena  which  are  to  be  seen 
in  some  of  the  chromacea  can  also  be  explained  by 

197 


THE    WONDERS    OF    LIFE 

physical  or  chemical  causes  on  mechanical  principles. 
Not  a  single  fact  compels  us  to  assume  a  "vital  force." 

Especially  noteworthy  in  regard  to  the  physiological 
character  of  these  lowest  organisms  are  their  bionomic 
peculiarities,  especially  the  indifference  to  external  in- 
fluences, higher  and  lower  temperatures,  etc.  Many 
of  the  chromacea  live  in  hot  springs,  with  a  temperature 
of  fifty  to  eighty  degrees  centigrade,  in  which  no  other 
organism  is  found.  Other  species  may  remain  for  a 
long  time  frozen  in  ice,  and  resume  their  vital  activity 
as  soon  as  it  thaws.  Many  chromacea  may  be  com- 
pletely dried  up,  and  then  resume  their  life  if  put  in 
water  after  several  years. 

Next  in  order  to  the  chromacea  we  have  the  bacteria, 
the  remarkable  little  organisms  which  have  been  well 
known  in  the  last  few  decades  as  the  causes  of  fatal 
diseases,  and  the  agents  of  fermentation,  putrefaction, 
etc.  The  special  science  which  is  concerned  with  them — 
modern  bacteriology — has  attained  so  important  a  posi- 
tion in  a  short  period — especially  as  regards  practical 
and  theoretical  medicine — that  it  is  now  represented  by 
separate  chairs  at  most  of  the  universities.  We  may 
admire  the  penetration  and  the  perseverance  with  which 
scientists  have  succeeded,  with  the  aid  of  the  best 
modern  microscopes  and  methods  of  preparation  and 
coloring,  in  making  so  close  a  study  of  the  organism  of 
the  bacteria,  determining  their  physiological  properties, 
and  explaining  their  great  importance  for  organic  life 
by  careful  experiments  and  methods  of  culture.  The 
bionomic  or  economic  position  of  the  bacteria  in 
nature's  household  has  thus  secured  for  these  tiny 
organisms  the  greatest  scientific  and  practical  interest. 

However,  we  find  that  certain  general  views  have  been 
maintained  by  specialists  in  bacteriology  up  to  our  own 
time  which  are  in  curious  contrast  with  these  brilliant 
results.     The    biologist    who    studies    the    systematic 

198 


M  0  N  E  R  A 

relations  of  the  bacteria  from  the  modern  point  of  view 
of  the  theory  of  descent  is  bewildered  at  the  extraor- 
dinary views  as  to  the  place  of  the  bacteria  in  the 
plant-world  (as  segmentation-fungi),  their  relations  to 
other  classes  of  plants,  and  the  formation  of  their 
species.  When  we  carefully  consider  the  morphological 
properties  that  are  common  to  all  true  bacteria  and 
compare  them  with  other  organisms,  we  are  forced  to  the 
conclusion  that  I  urged  years  ago  in  various  writings: 
the  bacteria  are  not  real  (nucleated)  cells,  but  un- 
nucleated  cytodes  of  the  rank  of  the  monera;  they  are 
not  real  (tissue-forming)  fungi,  but  simple  protists; 
their  nearest  relatives  are  the  chromacea. 

The  individual  organisms  of  the  simplest  kind,  which 
bacteriologists  call  "bacteria-cells,"  are  not  real  nucle- 
ated cells.  That  is  the  clear  negative  result  of  a  number  of 
most  careful  investigations  which  have  been  made  up  to 
date  with  the  object  of  finding  a  nucleus  in  the  plasma- 
body  of  the  bacteria.  Among  recent  exact  investigations 
we  must  especially  note  those  of  the  botanist  Reinke, 
of  Kiel,  who  sought  in  vain  to  detect  a  nucleus  in  one 
of  the  largest  and  most  easily  studied  genera  of  the 
bacteria,  the  beggiatoa,  using  every  modern  technical 
aid.  His  conviction  that  this  important  cell-structure 
is  really  lacking  is  the  more  valuable,  as  it  is  very 
prejudicial  to  his  own  theory  of  "dominants."  Other 
scientists  (especially  Schaudinn)  have  recently  claimed, 
as  equivalent  to  a  nucleus  in  some  of  the  larger  bacteria, 
a  number  of  very  small  granules,  which  are  irregularly 
distributed  in  the  plasm,  and  are  strongly  tinted  under 
certain  coloring  processes.  But  even  if  the  chemical 
identity  of  these  substances  which  take  the  same  color 
were  proved — which  is  certainly  not  the  case — and  even 
if  the  appearance  of  scattered  nuclein-granules  in  the 
plasm  could  be  regarded  as  a  preliminary  to,  or  a 
beginning    of,    the    differentiation    of    an    individual, 

199 


THE    WONDERS    OF    LIFE 

morphologically  distinct  nucleus,  we  should  not  yet  have 
shown  its  independence  as  an  organellum  of  the  cell. 

Nor  is  this  any  more  proved  from  the  circumstance 
that  in  some  bacteria  (not  all)  we  find  a  severance  of  the 
plasm  into  an  inner  and  outer  layer,  or  a  frothy  structure 
with  vacuole-formation,  or  a  special  sharply  outlined 
membrane  on  the  plastid.  Many  bacteria  (but  not  all) 
have  such  a  membrane,  like  the  nearly  related  chromacea, 
and  also  the  secretion  of  a  gelatine  envelope.  Both 
classes  have  also  in  common  an  exclusively  monogenetic 
reproduction.  The  bacteria  multiply,  like  the  chromacea, 
by  simple  segmentation;  as  soon  as  the  structureless 
plasma-granule  has  reached  a  certain  size  by  simple 
growth,  it  is  constricted  and  splits  into  two  halves.  In 
the  long-bodied  bacteria  (the  rod-shaped  bacilli)  the 
constriction  always  goes  through  the  middle  of  the  long 
axis,  and  is,  therefore,  simple  transverse  cleavage.  Many 
bacteria  have  also  been  said  to  multiply  by  the  forma- 
tion of  spores.  But  these  so-called  "spores"  are  really 
permanent  quiescent  forms  (without  any  multiplication 
of  individuals) ;  the  central  part  of  the  plastid  (endo- 
plasm)  condenses,  separates  from  the  peripheral  part 
(exoplasm),  and  undergoes  a  chemical  change  which 
makes  it  very  indifferent  to  external  influences  (such  as 
a  high  temperature). 

The  great  majority  of  the  bacteria  differ  so  little  mor- 
phologically from  the  chromacea  that  we  can  only  dis- 
tinguish these  two  classes  of  monera  by  the  difference  in 
their  metabolism.  The  chromacea,  as  protophyta,  are 
plasmodomous.  They  form  new  plasm  by  synthesis  and 
reduction  from  simple  inorganic  compounds — water, 
carbonic  acid,  ammonia,  nitric  acid,  etc.  But  the 
bacteria,  as  protozoa,  are  plasmophagous.  They  cannot, 
as  a  rule,  form  new  plasm,  but  have  to  take  it  from 
other  organisms  (as  parasites,  saprophytes,  etc.);  they 
decompose  it  by  analysis  and  oxydation.     Hence  the 

200 


MONERA 

colorless  bacteria  are  without  the  important  green, 
blue,  or  red  coloring  matter  (phycocyan)  which  tints 
the  plastids  of  the  chromacea,  and  is  the  real  instrument 
of  the  carbon-assimilation.  However,  there  are  excep- 
tions in  this  respect:  bacillus  virens  is  tinted  green  with 
chlorophyll,  micrococcus  prodigiosus  is  blood-red,  other 
bacteria  purple,  and  so  on.  Certain  earth-dwelling 
bacteria  {nitrobacteria)  have  the  vegetal  property  of 
plasmodomism ;  they  convert  ammonia  by  oxydation 
into  nitrous  acid,  and  this  into  nitric  acid,  using  as  their 
source  of  carbon  the  carbonic  acid  gas  in  the  atmosphere. 
They  are  thus  quite  independent  of  organic  substances, 
and  feed,  like  the  chromacea,  on  simple  inorganic  com- 
pounds. 

Hence  the  ai^nity  between  the  plasmodomous  chro- 
macea and  plasmophagous  bacteria  is  so  close  that  it  is 
impossible  to  give  a  single  safe  criterion  that  will  effect- 
ually separate  the  two  classes.  Many  botanists  accord- 
ingly combine  both  groups  in  a  single  class  with  the 
name  of  schizophyta,  and  within  this  distinguish  as 
"orders"  the  blue-green  chromacea  as  schizophyccce 
(cleavage  -  algae)  and  the  colorless  bacteria  as  scJiizo- 
mycetes  (cleavage-fungi).  However,  we  must  not  take 
this  division  too  rigidly;  and  the  absolute  lack  of  a  nu- 
cleus and  tissue-formation  separates  the  chromacea  just 
as  widely  from  the  multicellular  tissue-forming  algae  as 
the  bacteria  from  the  fungi.  The  simple  multiplication 
by  the  halving  of  the  cell,  which  is  expressed  in  the  name 
"cleavage-plants"  {schizophyta),  is  also  found  in  many 
other  protists. 

The  number  of  forms  that  can  be  distinguished  as 
species  in  the  technical  sense  is  very  great  in  the  case  of 
the  bacteria,  in  spite  of  the  extreme  simplicity  of  their 
outward  appearance;  many  biologists  speak  of  several 
hundred,  and  even  of  more  than  a  thousand,  species. 
But  when  we  look  solely  to  the  outer  form  of  the  living 

20I 


THE    WONDERS    OF    LIFE 

plasma-granule,  we  can  only  distinguish  three  funda- 
mental types:  (i)  Micrococci,  or  spherobacteria  (briefly, 
cocci),  globular  or  ellipsoid;  (2)  bacilli,  or  rhabdo-bac- 
teria  (also  called  eubacteria,  or  bacteria  in  the  narrower 
sense),  rod-shaped,  cylindrical,  and  often  twisted  like 
worms  (comma-bacilli) ;  (3)  spirilla,  or  spirobacteria, 
screw-shaped  rods  (vibriones  when  the  screw  is  slight, 
and  spirochaeta  when  it  has  many  coils).  Besides  this 
threefold  difference  in  the  forms  of  the  cytodes,  we 
have  a  ground  of  distinction  in  many  bacilli  and  spirilla 
in  the  possession  of  one  or  more  very  thin  lashes  (fla- 
gella),  which  proceed  from  one  of  both  poles  of  the 
lengthened  plastid.  The  construction  and  vibration  of 
these  serves  for  locomotion  in  the  swimming  bacteria; 
but  they  are  only  found  for  a  time  in  many  species,  and 
in  many  others  are  altogether  wanting. 

Since,  then,  neither  the  simple  outer  form  of  the 
bacterium  -  cytodes  nor  their  homogeneous  internal 
structure  provides  a  satisfactory  ground  for  the  sys- 
tematic distinction  of  the  numerous  species,  their  physio- 
logical properties  are  generally  used  for  the  purpose, 
especially  their  different  behavior  towards  organic  foods 
(albumin,  gelatine,  etc.),  their  chemical  actions,  and  the 
various  effects  of  poisoning  and  decomposition  which 
they  produce  in  the  living  organism.  No  bacteriologist 
now  doubts  that  all  the  vital  activities  of  the  bacteria 
are  of  a  chemical  nature,  and  precisely  on  this  account 
these  microbes  are  of  extreme  importance.  When  we 
bear  in  mind  how  complicated  are  the  relations  of  the 
various  species  of  bacteria  to  the  tissues  of  the  human 
body,  in  which  they  cause  the  diseases  of  typhus,  hypo- 
chondriasis, cholera,  and  tuberculosis,  we  are  bound  to 
admit  that  the  real  cause  of  these  maladies  must  be 
sought  in  the  peculiar  molecular  structure  of  the  bac- 
terium-plasm, or  the  particular  arrangement  of  its  mole- 
cules and  the  innumerable  atoms  (more  than  a  thousand) 

202 


M  O  N  E  R  A 

which  are,  in  a  very  loose  way,  made  up  into  special 
groups  of  molecules.  The  chemical  products  of  their 
mutual  action  are  what  we  call  ptomaines,  which  are 
partly  very  virulent  poisons  (toxins).  We  have  suc- 
ceeded in  producing  several  of  these  poisonous  matters 
in  large  quantities  by  artificial  culture,  and  isolating  them 
and  experimentally  ascertaining  their  nature;  as,  for 
instance,  tetanin,  which  causes  tetanus,  typhotoxin,  the 
poison  of  typhus,  etc. 

In  thus  declaring  the  action  of  bacteria  to  be  purely 
chemical  and  analogous  to  that  of  well-known  inorganic 
poisons,  I  would  particularly  point  out  that  this  very 
justifiable  statement  is  a  pure  hypothesis;  it  is  an  excel- 
lent illustration  of  the  fact  that  we  cannot  get  on  in  the 
explanation  of  the  most  important  natural  phenomena 
without  hypotheses.  We  can  see  nothing  whatever  of 
the  chemical  molecular  structure  of  the  plasm,  even 
under  the  highest  power  of  the  microscope;  it  lies  far 
below  the  limit  of  microscopic  perception.  Neverthe- 
less, no  expert  scientist  has  the  slightest  doubt  of  its 
existence,  or  that  the  complicated  movements  of  the 
sensitive  atoms  and  the  molecules  and  groups  of  mole- 
cules they  make  up  are  the  causes  of  the  vast  changes 
which  these  tiny  organisms  effect  in  the  tissues  of  the 
human  and  the  higher  animal  body. 

Moreover,  the  distinction  of  the  many  species  of  bac- 
teria is  of  interest  in  connection  with  the  general  ques- 
tion of  the  nature  and  constancy  of  a  species.  Whereas 
formerly  in  biological  classification  only  definite  mor- 
phological characters,  or  definable  differences  in  outer 
form  or  inner  structure,  were  regarded  as  of  any  moment 
in  the  distinction  of  species,  here,  in  view  of  the  vague- 
ness or  total  lack  of  these  characters,  we  have  to  look 
mainly  to  the  physiological  properties,  and  these  are 
based  on  the  chemical  differences  in  their  hypothetical 
molecular  structure.     But  even  these  are  not  absolutely 

203 


THE    WONDERS    OF    LIFE 

constant;  on  the  contrary,  many  bacteria  lose  their 
specific  qualities  by  progressive  culture  under  changed 
food-conditions.  By  a  change  in  the  temperature  and 
the  nutritive  field  in  which  a  number  of  poisonous  bac- 
teria have  been  reared,  or  by  the  action  of  certain 
chemicals,  not  only  the  growth  and  multiplication  are 
altered,  but  also  the  injurious  effect  they  have  on  other 
organisms  by  the  generation  of  poisons.  This  poisonous 
effect  is  weakened,  and — what  is  most  important — the 
weakening  is  transmitted  by  heredity  to  the  following 
generations.  On  this  is  based  the  familiar  process  of 
inoculation,  an  admirable  example  of  the  inheritance  of 
acquired  characteristics. 

As  the  bacteria  are  still  often  described  as  "cleavage- 
fungi"  and  classified  along  with  the  real  fungi,  we  must 
particularly  point  out  the  wide  gulf  that  separates  the 
two  groups.  The  real  fungi  (or  mycetes)  are  metaphyta, 
their  multicellular  body  (thallus)  forming  a  very  char- 
acteristic sort  of  tissue,  the  mycelium;  this  is  composed 
of  a  number  of  interlaced  and  interwoven  threads  (or 
hyphens).  Each  fungus-thread  consists  of  a  row  of 
lengthened  cells,  which  have  a  thin  membrane  and  en- 
close a  number  of  small  nuclei  in  the  colorless  plasm. 
Moreover,  the  two  sub-classes  of  the  real  fungi,  the 
ascomycetes  and  basimycetes,  form  peculiar  fruit-bodies 
which  generate  spores  (ascodia  and  basidia).  There  is 
no  trace  whatever  of  these  real  characteristics  of  the 
true  fungus  in  the  bacteria.  Nor  is  it  less  incorrect  to 
class  them  with  the  fungilli,  the  so-called  unicellular 
fungi  or  phycomycetes  (ovomycetes  and  zygomycetes) ; 
these  form  a  special  class  of  protists  which  has  the  closest 
affinity  to  the  gregarinae. 

Like  the  closely  related  chromacea,  many  of  the  bac- 
teria show  a  marked  tendency  to  form  communities  or 
cell-colonies.  These  cell-communities  arise,  as  else- 
where, from  the  fact  that  the  individuals,  which  multi- 

204 


M  O  N  E  R  A 

ply  rapidly  by  continuous  cleavage,  remain  joined  to- 
gether. This  may  hap])en  in  two  ways.  When  the 
social  bacteria  secrete  large  quantities  of  gelatine,  and 
remain  distributed  in  this,  we  have  the  zoogloca  (as  in  the 
case  of  the  aphanocapsa  and  glceocapsa  among  the  chro- 
macea).  If,  on  the  other  hand,  the  long-bodied  bacilli 
remain  fastened  together  in  rows,  we  get  the  knotted 
threads  of  Icptoihrix  and  heggiatoa  (which  may  be  com- 
pared with  the  oscillaria).  And,  if  these  threads  go  into 
branches,  we  have  cladothrix.  Other  coenobia  of  bac- 
teria have  the  appearance  of  disks,  the  cytodes  dividing 
in  a  plane,  usually  in  groups  of  four  (as  in  mcrismopcdia), 
or  of  cube-shaped  packets  when  they  are  in  all  three 
directions  of  space  (sarcina). 

The  two  classes  of  bacteria  and  chromacea  seem,  in 
the  present  condition  of  our  knowledge,  on  account  of 
their  simple  organization,  to  be  the  simplest  of  all  living 
things,  real  monera,  or  organisms  without  organs. 
Hence  we  have  to  put  them  at  the  lowest  stage  of  the 
protist  kingdom,  and  must  regard  the  difference  between 
them  and  the  most  highly  differentiated  unicellular 
beings  (such  as  the  radiolaria,  ciliated  infusoria,  dia- 
tomes,  or  siphonea)  as  no  smaller  than  the  difference 
(in  the  realm  of  the  histona)  between  a  lower  polyp 
(hydra)  and  a  vertebrate,  or  between  a  simple  alga  (ulva) 
and  a  palm.  But  if  the  kingdom  of  the  pirotists  is  badly 
divided,  on  the  older  rule,  into  a  plant  kingdom  and  an 
animal  kingdom,  the  only  discriminating  mark  we  have 
left  is  the  difference  in  metabolism ;  in  that  case  we  have 
to  include  the  plasmophagous  bacteria  in  the  animal 
kingdom  (as  Ehrenberg  did  in  1838)  and  the  plasmo- 
domous  chromacea  in  the  plant  kingdom.  The  remark- 
able class  of  the  fiagellata,  which  includes  ciliated  uni- 
cellulars  of  both  groups,  contains  several  forms  which 
are  only  distinguished  from  the  typical  bacterium  by 
the  possession  of  a  nucleus.     If  it  is  true  that  in  some  of 

205 


THE    WONDERS    OF    LIFE 

the  protists  which  were  counted  as  bacteria  a  real  nu- 
cleus has  been  detected,  these  must  be  separated  from 
the  others  (unnucleated)  and  included  in  the  nucleated 
flagellata. 

The  monera  which  I  described  in  1866,  and  on  which 
I  based  the  theory  of  the  monera  in  my  monograph, 
belong  to  a  different  division  of  the  protists  from  the 
classes  of  bacteria  and  chromacea.  These  are  the  forms 
which  I  described  as  protamceba,  protogenes,  protomyxa, 
etc.  Their  naked  mobile  plasma -bodies  thrust  out 
pseudopodia,  or  variable  "false  feet,"  from  their  surface, 
like  the  (nucleated)  real  rhizopods  (  =  sarcodinae);  but 
they  differ  essentially  from  the  latter  in  the  absence  of  a 
nucleus.  Afterwards  (in  my  Systematic  Phylogeny)  I 
proposed  to  separate  these  unnucleated  rhizopods  from 
the  others,  giving  the  name  of  lobomonera  (protamceba) 
to  the  amoeba-like  monera  with  flap-shaped  feet,  and 
the  name  of  rhizomonera  {protomyxa,  pontomyxa,  bio- 
myxa,  arachmda,  etc.)  to  the  gromia-like,  root-feet  form- 
ing monera.  However,  of  late  years,  real  nuclei  have 
been  detected  in  each  of  these  large  monera,  and  so  they 
have  been  proved  to  be  true  cells.  This  discovery  was 
made  possible  by  the  improved  modern  methods  of  col- 
oring the  nucleus  which  I  had  not  the  use  of  thirty  years 
ago  in  my  first  observations.  On  the  strength  of  these 
recent  discoveries  many  scientists  claim  that  all  the 
monera  I  described  are  true  cells,  and  must  have  nuclei, 
This  baseless  assertion  is  much  employed  by  the  op- 
ponents of  the  theory  of  evolution  in  order  to  deny  the 
existence  of  the  monera  altogether. 

Of  the  genus  of  monera  which  we  call  protamoeba  I 
have  given  an  illustration  in  my  History  of  Creation 
(tenth  edition),  which  has  been  frequently  reproduced. 
Several  species  (at  least  two  or  three)  of  this  genus  still 
exist,  and  are  distinguished  by  the  shape  of  their  flap- 
formation  and  their  method  of  motion.     They  resemble 

206 


M  O  N  E  R  A 

ordinary  simple  amoebae,  and  only  differ  from  these  to 
any  extent  in  the  absence  of  a  nucleus.  The  protamocha 
primitiva  seems  to  be  pretty  widely  distributed;  it  has 
been  found  repeatedly  by  observers  (Gruber,  Cienkow- 
ski,  Leidy,  etc.)  in  inland  waters.  In  the  zoological 
demonstrations  which  I  have  given  at  the  University  of 
Jena  for  forty  years,  and  in  the  course  of  which  the  low- 
ly inhabitants  of  our  fresh  water  are  regularly  examined 
with  the  microscope,  the  protamccha  primitiva  has  been 
found  four  or  five  times.  It  always  had  the  same  form, 
as  I  described  it,  moved  about  by  the  slow  formation  of 
flaps  at  its  surface,  multiplied  by  simple  cleavage,  and 
showed  no  trace  of  a  nucleus  in  its  homogeneous  plasma- 
body  even  with  the  most  careful  application  of  the 
modern  methods  of  tinting  the  nucleus.  A  larger  num- 
ber of  very  fine  granules  (microsoma)  that  were  irregu- 
larly distributed  in  the  plasm,  and  were  more  or  less 
colored  by  nucleus-reagents,  cannot  be  reckoned  as  clear 
equivalents  of  the  nucleus  in  this  or  in  similar  cases; 
they  are  probably  products  of  metabolism.  The  same 
may  be  said  of  the  larger  marine  form  of  rhizomoneron, 
which  A.  Gruber  has  recently  called  pclomyxa  pallida. 

The  large  marine  form  of  rhizomoneron  to  which 
Huxley  gave  the  name  of  hathyhius  Hccckclii  in  1868, 
and  as  to  the  real  nature  of  which  many  opinions  have 
been  expressed,  seems,  according  to  the  latest  investi- 
gation, not  to  have  the  significance  ascribed  to  it.  How- 
ever, the  much-discussed  question  of  the  bathybius  is 
superfluous  as  far  as  our  monera  theory  and  the  as- 
sociated hypothesis  of  archigony  (chapter  xv.)  are  con- 
cerned, since  we  have  now  a  better  knowledge  of  the 
much  more  important  monera-forms  of  the  chromacea 
and  bacteria. 

In  the  case  of  some  of  the  protists  I  described  in  my 
Monograph  on  the  Monera,  it  is  at  present  doubtful 
whether  their  plasma-body  contains  a  nucleus  or  not, 

207 


THE    WONDERS    OF    LIFE 

and,  therefore,  whether  they  are  to  be  classed  as  true 
cells  or  cytodes.  This  applies  especially  to  the  forms 
which  only  happened  to  come  under  observation  once, 
such  as  protomyxa  and  niyxastrmn.  In  these  obscure 
cases  we  must  wait  for  fresh  investigations  and  the  ap- 
plication of  the  modern  methods  of  tinting  the  nucleus. 
I  may,  however,  point  out,  in  passing,  that  these  famous 
methods  of  nucleus-coloring  give  by  no  means  the  abso- 
lute certainty  which  is  ascribed  to  them ;  there  are  other 
substances  which  take  color  in  the  same  way  as  chro- 
matin. As  far  as  my  monera  theory  is  concerned,  or 
the  great  general  importance  which  I  attach  to  these 
unnucleated  living  granules  of  plasm,  it  does  not  matter 
whether  a  nucleus  is  detected  in  these  problematic 
monera  or  not.  The  chromacea  alone — the  most  im- 
portant of  all  monera — completely  suffice  to  provide  a 
base  for  the  far-reaching  theoretical  conclusions  which  I 
draw  from  it. 

At  the  close  of  these  observations  on  the  monera  I 
will  briefly  recapitulate  the  weighty  inferences  which  we 
can  deduce  from  their  simple  organization.  They  serve 
as  a  solid  foundation  for  the  chief  theses  of  our  monistic 
biology;  and  they  are  inconsistent  with  the  dualistic 
views  of  modern  vitalists.  In  the  first  place,  I  empha- 
size the  fact  that  the  structureless  plasm-body  of  the 
simple  monera  has  no  sort  of  organization  and  no  com- 
position from  dissimilar  parts  co-operating  for  definite 
vital  aims.  Reinke's  conscious  "dominant" — as  well 
as  Weismann's  mechanical  "determinants" — have  noth- 
ing to  do  here.  The  whole  vital  activity  of  the  simplest 
monera,  especially  of  the  chromacea,  is  confined  to  their 
metabolism,  and  is  therefore  a  purely  chemical  process, 
that  may  be  compared  to  the  catalysis  of  inorganic  com- 
pounds. The  simple  formation  of  individuals  in  this 
primitive  living  matter  is  merely  a  question  of  the  cleav- 
age of  plasma  globules  of  a  certain  size  (chroococcus) ; 

208 


MONERA 

and  their  primitive  multiplication  (by  simple  self -di- 
vision) is  only  a  continued  growth  (analogous  to  that  of 
the  crystal).  When  this  simple  growth  passes  a  certain 
limit,  that  is  fixed  by  the  chemical  constitution,  it  leads 
to  the  independent  existence  of  the  redundant  growth- 
products. 
14 


X 

NUTRITION 

Functions  of  nutrition — Assimilation  and  disassimilation — 
Plasmodoma  and  plasmophaga — Phytoplasm  and  zooplasm 
— Plasmodomism  of  plants — Chlorophyll  granules  and  nitro- 
bacteria— Plasmophagism  of  fungi  and  animals — Metasi- 
tism  (conversion  of  metabolism) — Nutrition  of  the  monera 
(chromacea,  bacteria,  rhizomonera) — Nutrition  of  the 
protophyta  and  metaphyta  (cell-plants  and  tissue-plants) — 
Nutrition  of  the  metazoa — Gastraea  theory — Gastro-canal 
system  of  the  coelenteria  (gastraeads,  sponges,  cnidaria, 
platodes) — Nutrition  of  the  coelomaria  (digestion,  circula- 
tion, respiration,  evacuation) — Saprositism — Parasitism — 
Symbiosis. 

THE  wonder  of  life  which  we  call,  in  the  wildest  sense 
of  the  word,  "nutrition"  is  the  chief  factor  in  the 
self-maintenance  of  the  organic  individual.  It  is  always 
bound  up  with  a  chemical  modification  of  the  living 
matter,  an  organic  metabolism  (circulation  of  matter), 
and  a  corresponding  circulation  of  force.  In  this 
chemical  process  plasm  is  used  up,  built  up  afresh,  and 
once  more  disintegrated.  The  metabolism  which  lies  at 
the  root  of  this  chemistry  of  food  is  the  essential  feature 
in  the  manifold  processes  of  nutrition.  A  large  part  of 
the  several  nutritive  processes  are  explained  without 
further  trouble  by  the  known  physical  and  chemical 
properties  of  inorganic  bodies;  for  another  part  of  them 
we  have  not  yet  succeeded  in  doing  this.  Nevertheless, 
all  impartial  physiologists  now  agree  that  it  is  possible 
in  principle,  and  that  we  have  no  reason  to  introduce 

2lO 


NUTRITION 

a  special  vital  principle.  All  the  trophic  (nutritive) 
processes,  without  exception,  are  subject  to  the  law  of 
substance. 

In  all  the  higher  plants  and  animals  the  chemical' 
process  of  metabolism,  with  the  stream  of  energy  that 
accompanies  it,  is  a  very  complex  vital  activity,  in  which 
many  different  functions  and  organs  co-operate  with 
the  common  aim  of  self-maintenance.  As  a  rule,  they 
are  distributed  in  four  groups — namely :  ( i )  Intussuscep- 
tion of  food  and  digestion:  (2)  distribution  of  the  food 
in  the  body,  or  circulation;  (3)  respiration,  or  exchange 
of  gases;  and  (4)  excretion  of  unusable  matter.  In 
most  of  the  histona,  either  tissue-plants  or  tissue- 
animals,  a  number  of  organs  are  differentiated  for  the 
accompHshment  of  these  tasks.  At  the  lower  stages  of 
life  this  division  of  labor  is  not  found,  the  entire  proc- 
ess of  nutrition  being  accomplished  by  a  single  layer 
of  cells  (lower  algae,  gastra^ads,  sponges,  lower  polyps). 
In  the  protists,  again,  it  is  the  single  cell  that  does 
all  these  things  itself;  in  the  simplest  cases,  the  monera, 
a  homogeneous  plasma-globule.  As  a  long  gradation 
uninterruptedly  unites  these  lowest  forms  of  nutrition 
with  the  more  complicated  forms,  we  must  regard  the 
latter    no    less    than   the   former    as    physico-chemical 

processes. 

When  we  take  the  whole  of  the  metabolic  functions  in 
organisms  together,  we  may  look  upon  them  as  the  out- 
come of  two  opposite  chemical  processes — on  the  one 
hand  the  building-up  of  living  matter  by  taking  in  food 
(assimilation),  and  on  the  other  the  breaking-down  of  it 
in  consequence  of  its  vital  activity  (disassimilation).  As 
in  every  case  the  plasm  is  the  active  living  matter,  we 
may  say:  Assimilation  (or  plasma-production)  consists 
in  the  conversion  within  the  organism  into  the  special 
plasm  of  the  particular  species  of  food  that  has  been 
received    from    without;     disassimilation    (or    plasma- 

211 


THE    WONDERS    OF    LIFE 

destruction)  is  the  result  of  the  work  done  by  the  plasm, 
which  is  the  cause  of  its  partial  decomposition  or  break- 
down. In  both  respects  there  is  a  striking  difference 
between  the  two  great  kingdoms  of  organic  nature.  The 
plant  kingdom  is,  on  the  whole,  the  agent  of  assimilation, 
forming  new  plasm  by  synthesis  and  reduction  from 
inorganic  matter.  In  the  animal  world,  on  the  contrary, 
disassimilation  preponderates,  the  plasm  received  being 
resolved  by  oxydation,  and  the  actual  energy  taken  out 
of  it  by  analysis  being  converted  into  heat  and  motion. 
Plants  are  plasmodomous ;  animals,  plasmophagous. 

Of  all  the  chemical  processes  the  miost  important, 
because  the  most  indispensable,  for  the  origin  and 
maintenance  of  organic  life  is  the  constant  reconstruc- 
tion of  plasm.  We  give  it  the  name  of  plasmodomism 
{domeo  =.  to  build  up),  or  carbon-assimilation.  Botanists 
have  the  habit  of  late  of  calling  it  briefly  assimilation, 
and  have  thus  caused  a  good  deal  of  misunderstanding. 
The  more  common  and  older  meaning  of  assimilation  in 
animal  physiology  is,  in  the  widest  sense,  the  intussus- 
ception and  preparation  of  the  food  received.  But  the 
carbon  -  assimilation  in  plants  —  what  I  call  plasmo- 
domism— is  only  the  first  and  original  form  of  plasma- 
production.  It  means  that  the  plant  is  able,  under  the 
influence  of  sunlight,  to  form  carbo-hydrates,  and  from 
these  new  plasm,  out  of  simple  inorganic  compounds 
(water,  carbonic  acid,  nitric  acid,  and  ammonia)  by 
synthesis  and  reduction.  The  animal  is  unable  to  do 
this.  It  has  to  take  its  plasm  in  its  food  from  other 
organisms — plant-eaters  directly,  and  animal-eaters  in- 
directly. We  therefore  give  the  title  of  plasmophagous 
to  these  animal  "plasma-eaters."  In  working  up  the 
foreign  plasm  it  has  eaten,  and  converting  it  into  its 
own  specific  form  of  plasm,  the  animal  also  accomplishes 
assimilation;  but  this  animal  albumin-assimilation  is 
totally  different  from  the  vegetal  carbon-assimilation. 

212 


NUTRITION 

The  fresh-formed  animal  plasm  is  then  broken  up  by 
oxydation,  and  by  this  analysis  the  energy  needed  for 
the  vital  movements  is  obtained. 

The  physiological  contrast  which  we  thus  find  between 
the  two  principal  forms  of  living  matter,  the  synthetic 
plasm  of  the  plant  and  the  analytic  plasm  of  the  animal, 
is  of  great  importance  for  the  lasting  maintenance 
of  the  whole  organic  world.  It  depends  on  a  reversal 
of  the  molecular  movement  in  the  plasm,  the  intimate 
nature  of  which  is  just  as  little  known  to  us  as  the 
chemical  constitution  of  the  albumins  in  general,  and 
that  of  living  albumin,  the  plasm,  in  particular.  As  I 
mentioned  in  chapter  v.,  modern  physiological  chemistry 
has  good  reason  to  believe  that  the  invisible  albumin- 
molecule  is,  comparatively  speaking,  gigantic,  and  is 
composed  of  more  than  a  thousand  atoms.  These 
are  in  such  an  unstable  equilibrium,  so  complicated  and 
impermanent  an  arrangement,  that  the  slightest  push  or 
stimulus  suffices  to  alter  them  and  form  a  new  kind  of 
plasm.  As  a  fact,  the  number  and  variety  of  kinds  of 
plasm  are  immense.  This  is  seen  at  once  from  the 
ontogenetic  fact  that  the  ovum  and  sperm-cell  of  each 
species  (and  each  variety)  have  a  specific  chemical 
constitution.  In  reproduction  this  is  transmitted  to  the 
offspring.  But,  setting  aside  these  countless  finer 
modifications,  we  may  distinguish  two  chief  groups  of 
kinds  of  plasm:  the  phytoplasm  of  the  plant,  with  the 
synthetic  property  of  plasmodomism,  and  the  zooplasm 
of  the  animal,  which  is  destitute  of  this  property,  and  so 
confined  to  plasmophagy. 

The  remarkable  synthetic  process  of  building  up  the 
plasm,  to  which  we  give  the  name  of  plasmodomism,  or 
carbon-assimilation,  usually  needs  as  its  first  condition 
the  radiant  energy  of  sunlight.  Every  green  plant-cell 
contains  in  its  chlorophyll-granules  so  many  tiny  labora- 
tories, their  green  plasm  being  able  to  form  new  plasm 

213 


THE    WONDERS    OF    LIFE 

out  of  inorganic  compounds  under  the  influence  of  light. 
The  water  that  is  needed  for  this,  besides  nitrogenous 
compounds  (nitric  acid,  ammonia),  is  drawn  from  the 
earth  by  the  roots;  the  carbonic  acid  is  taken  from  the 
atmosphere  by  the  green  leaves.  The  immediate  prod- 
ucts of  the  synthesis,  due  to  the  separation  of  the 
carbonic  acid,  is,  as  a  rule,  a  non-nitrogenous  starch-flour 
(amylum).  This  is  further  used  for  the  composition 
of  the  nitrogenous  albumin  by  an  as  yet  unknown 
synthetic  process,  with  the  aid  of  nitrogenous  mineral 
compounds.  In  this  process  of  reduction  the  separated 
free  oxygen  is  returned  to  the  atmosphere.  The  carbo- 
hydrates that  chiefly  co-operate  in  this  are  glucoses 
and  maltoses :  the  mineral  substances,  especially  salts  of 
potassium  and  magnesium,  and  compounds  of  these 
elements  with  nitric  acid,  sulphuric  acid,  and  phosphoric 
acid.  Iron  is  also  found  to  be  an  important  element  in 
the  process,  though  in  a  very  small  quantity.  As  a  rule, 
the  ferruginous  chlorophyll  can  only  form  new  plasm 
with  the  help  of  light-waves.  The  most  important  part 
of  the  spectrum  for  this  fjurpose  is  that  containing  the 
red,  orange,  and  yellow  waves. 

The  chief  factor  in  plasma-formation  in  the  organic 
world  is  the  photo -synthesis,  or  ordinary  carbon- 
assimilation  by  chlorophyll,  the  wonderful  green  matter 
that  amounts  to  only  a  very  small  percentage  (about  one- 
tenth)  of  the  weight  of  the  chlorophyll-granules,  and  can 
be  separated  from  their  plasmatic  substance  by  certain 
methods.  Even  when  the  plant  has  some  other  color 
than  green  the  chlorophyll  is  still  the  real  plasmodomous 
substance.  Its  green  color  is  then  masked  by  some 
other  color  —  diatomin  in  the  yellow  diatomes,  phy- 
corhodin  in  the  red  rhodophyceae,  phycophaein  in  the 
brown  phasophyceae,  and  phyocyan  in  the  blue-green 
chromacea  or  cyanophyceae.  The  latter  have  an  especial 
interest  for  us,  because  in  the  simplest  specimens  the 

214 


NUTRITION 

entire  organism  is  merely  a  globular  bluish-green  granule 
of  plasm.  Moreover,  in  the  simplest  forms  of  nucleated 
primitive  plants  {ali^aricc) — many  of  the  so-called  uni- 
cellular algaj — the  metabolism  is  effected  by  a  single 
grain  of  chlorophyll.  There  is  usually  a  large  number 
of  them  in  the  plasm  of  the  plant-cells. 

Another  kind  of  plasm-synthesis,  quite  different  from 
the  ordinary  plasmodomism  by  chlorophyll  and  sunlight 
has  lately  been  discovered  in  some  of  the  lowest  organ- 
isms (by  Heraeus,  Winogradsky,  and  others).  The  nitro- 
bacteria (or  nitromonades)  are  tiny  monera  (unnucle- 
ated  cells)  that  live  in  complete  darkness  underground. 
Their  globular  colorless  plasma-bodies  contain  neither 
chlorophyll  nor  nucleus.  They  have  the  remarkable 
capacity  of  forming  carbo-hydrates,  and  from  these 
plasm,  by  a  peculiar  synthesis  out  of  purely  inorganic 
compounds — water,  carbonic  acid,  ammonia,  and  nitric 
acid.  Pfeffer  has  called  this  carbon-assimilation,  on 
account  of  its  purely  chemical  nature,  "chemosyn- 
thesis,"  in  opposition  to  the  ordinary  photosynthesis  by 
means  of  sunlight.  There  are  also  other  bacteria 
(sulphur -bacteria,  purple -bacteria,  etc.)  that  show 
various  peculiarities  of  metabolism.  The  nitro-bacteria 
must  belong  to  the  oldest  monera,  and  represent  a 
transition  from  the  vegetal  chromacea  to  the  animal 
bacteria. 

The  extensive  class  of  the  fungi  (or  niyccics)  resembles 
a  part  of  the  bacteria  in  regard  to  metabolism.  These 
organisms  are,  it  is  true,  generally  regarded  as  plants, 
but  they  have  not  the  capacity  of  the  green,  chlorophyll- 
bearing  plants  to  supply  themselves  with  carbon  from 
the  carbonic  acid  in  the  atmosphere.  They  have  to  take 
it  from  organic  substances,  such  as  albumin,  carbo- 
hydrates, etc.,  like  the  animals.  But  while  the  animals 
have  to  derive  their  nitrogen  from  the  latter,  the  fungi 
can  obtain  it  from  inorganic  matter  in  the  earth.    Fungi 

215 


THE    WONDERS    OF    LIFE 

cannot  support  life  without  the  addition  of  organic 
compounds;  but  we  can  make  them  grow  in  a  food 
solution  consisting  of  sugar  and  purely  inorganic  nitrog- 
enous salts.  Thus  they  are  on  the  border  that  separates 
the  plasmodomous  plants  from  the  plasmophagous 
animals.  Like  the  latter,  the  fungi  have  evolved  from 
the  plants  through  changed  food  conditions.  We  find 
this  process  even  among  the  unicellular  protists  in  the 
phycomycetes,  which  descend  from  the  siphonea.  In 
the  same  way  the  real  multicellular  fungi  (ascomycetes 
and  basimycetes)  may  be  traced  to  the  tissue-forming 
algce. 

All  true  animals  have  to  derive  their  food  from  the 
plant  kingdom,  the  vegetal  feeders  directly,  and  the  flesh 
feeders  indirectly,  when  they  consume  vegetal  feeders. 
Hence  the  animals  are,  in  a  certain  sense,  as  the  older 
natural  philosophy  put  it  four  hundred  years  ago, 
''parasites  of  the  plant  world."  From  the  point  of  view 
of  phylogeny,  the  animal  kingdom  is,  therefore,  clearly 
much  younger  than  the  plant  kingdom.  The  develop- 
ment of  the  animals  from  the  plants  was  determined 
originally  by  a  change  in  the  method  of  nutrition  which 
we  call  metasitism. 

The  chemical  modification  of  the  living  matter  which 
is  connected  with  the  loss  of  plasmodomism — in  other 
words,  the  conversion  of  the  reducing  phytoplasm  into 
oxidizing  zooplasm — must  be  regarded  as  one  of  the 
most  important  changes  in  the  history  of  organic  life. 
This  "reversal  of  metabolism"  is  polyphyletic ;  it  has 
been  repeated  many  times  in  the  course  of  biological 
history,  and  has  taken  place  independently  in  very 
different  groups  of  the  organic  world — whenever  a 
plasmodomous  cell  or  group  of  cells  (  =  tissue)  had 
occasion  to  feed  directly  on  ready-made  plasm,  instead 
of  giving  itself  the  trouble  of  building  it  up  out  of 
inorganic  compounds.     We  see  this  particularly  among 

216 


NUTRITION 

the  unicellular  protists  in  the  independent  ciliated  cells. 
The  longer  plasmophagous  flagellata,  which  are  color- 
less, and  have  no  chlorophyll  (monodina,  conoflagellata), 
closely  resemble  in  form  and  movement  the  older  plasma- 
domous  and  chlorophyll-bearing  mastigota,  from  which 
they  are  descended  (volvocina,  peridinia) ;  they  only 
differ  in  the  manner  of  nutrition.  The  colorless  flagel- 
lata feed  on  ready -formed  plasm,  which  they  obtain 
either  by  means  of  their  lashes  or  by  a  special  cell 
mouth  in  their  cell  body.  On  the  other  hand,  their 
ancestors,  the  green  or  yellow  mastigota,  form  new 
plasm  by  photosynthesis  like  true  cells.  But  there  are 
also  complete  intermediate  forms  between  the  two 
groups  —  for  instance,  the  chrysomonades  and  the 
gymnodinia;  these  may  behave  alternately  as  protozoa 
or  protophyta.  In  the  same  way  we  can  derive  the 
phycomycetes  by  metasitism  from  the  siphonea,  the 
fungi  from  the  algae;  and,  finally,  the  process  is  also 
found  in  many  of  the  higher  parasitic  plants  (orchids, 
orobanches,  etc.).     (See  under  "Parasitism.") 

As  is  the  case  with  every  other  vital  function,  so  for 
the  function  of  metabolism  we  find  a  starting-point  in 
the  lowest  and  simplest  group  of  the  protophyta,  the 
chromacea.  In  their  oldest  forms,  the  chroococcacea, 
the  whole  body  is  merely  a  blue-green,  structureless, 
globular  plasma  particle,  growing  by  means  of  its 
plasmodomous  power,  and  splitting  up  as  soon  as  it 
reaches  a  certain  stage  of  growth.  There  the  miracle  of 
life  consists  merely  of  the  chemical  process  of  plasmo- 
domism  by  photosynthesis.  The  sunlight  enables  the 
blue-green  phytoplasm  to  form  new  plasm  of  the  same 
kind  out  of  inorganic  compounds  (water,  carbonic  acid, 
ammonia,  and  nitric  acid).  We  may  look  upon  this 
process  as  a  special  kind  of  catalysis.  In  this  case 
there  is  absolutely  nothing  to  be  done  by  Reinke's 
"dominants,"  or  conscious  and  purposive  vital  forces. 

217 


THE    WONDER vS    OF    LIFE 

There  are,  as  yet,  no  differentiated  physiological  func- 
tions in  these  organisms  without  organs,  and  no  ana- 
tomically distinct  members;  and  so  their  one  vital 
activity,  growth,  may  very  well  be  compared  to  the 
simple  growth  of  inorganic  crystals. 

It  has  been  pointed  out  repeatedly  that  the  remarkable 
monera  which  now  play  so  important  a  part  in  biology 
as  bacteria  stand,  in  many  respects,  quite  apart  from 
the  ordinary  vital  phenomena  of  the  higher  organisms. 
This  is  especially  true  of  their  metabolism,  which  has 
the  most  striking  peculiarities.  Morphologically,  many 
of  the  bacteria  cannot  be  distinguished  from  their  near- 
est relatives  and  direct  ancestors,  the  chromacea,  differ- 
ing from  them  only  in  the  absence  of  coloring  matter  in 
the  plasm.  Many  of  them  are  simple,  globular,  ellipsoid, 
or  rod-shaped  plasma  particles,  without  any  visible  or- 
ganization or  movement.  Others  move  about  by  means 
of  one  or  more  very  fine  lashes  (like  the  flagellata).  No 
real  nucleus  can  be  discovered  in  the  structureless  plas- 
ma body.  The  very  fine  granules  which  are  found  in 
some  species,  and  the  vacuole-formation  that  we  see  in 
others,  may  be  regarded  as  products  of  metabolism; 
and  the  same  may  be  said  of  the  thin  membrane  or  the 
thicker  gelatinous  envelope  which  many  of  the  bacteria 
secrete.  This  makes  all  the  more  remarkable  the  pe- 
culiarity of  their  chemical  constitution  and  the  metab- 
olism determined  thereby.  The  nitro-bacteria  we  have 
mentioned  previously  are  plasmodomous ;  the  anaerobe 
bacteria  (of  butyric  acid  and  tetanus)  only  flourish 
where  oxygen  is  excluded ;  the  sulphur  bacteria  (beggia- 
toa)  secrete — by  the  oxydation  of  sulphuretted  hydro- 
gen— pure  regulation  sulphur  in  the  form  of  round  gran- 
ules. The  ferruginous  bacteria  {leptothrix  ochrocea)  store 
up  oxyhydrate  of  iron  (by  the  oxydation  of  carbonic 
protoxide  of  iron).  The  saprogenetic  bacteria  cause 
putrefaction,  and  the  zymogenetic  fermentation.     Final- 

218 


NUTRITION 

ly,  we  have  the  very  interesting  pathogenetic  bacteria 
which  cause  the  most  dangerous  diseases  Vjy  the  secretion 
of  special  poisons — toxins — festering,  small-pox,  teta- 
nus, diphtheria,  typus,  tuberculosis,  cholera,  etc.  On  ac- 
count of  their  great  practical  importance,  these  bacteria 
have  of  late  been  taken  over  by  a  special  branch  of  biol- 
ogy, bacteriology.  But  only  a  few  of  the  many  experts 
in  this  department  have  pointed  out  the  extreme  theo- 
retical significance  which  these  zoomonera  have  for  the 
important  questions  of  general  biology.  These  struct- 
ureless plasma  bodies  show  unmistakably  that  their 
vital  activity  is  a  purely  chemical  phenomenon.  Their 
great  variety  proves  how  manifold  and  complicated  must 
be  the  molecular  composition  of  the  plasm,  even  in  these 
simplest  organisms. 

The  unicellular  protophyta  exhibit  the  same  form  of 
metabolism  and  plasmodomism  as  the  familiar  green 
cells  of  the  tissue-plants ;  but  in  most  of  the  protozoa  we 
find  special  features  of  nutrition  and  plasmophagy.  The 
great  class  of  the  rhizopods  is  distinguished  by  the  fact 
that  their  naked  plasma  body  can  take  in  ready-fonned 
solid  food  at  any  point  of  its  surface.  On  the  other 
hand,  most  of  the  infusoria  have  a  definite  mouth-open- 
ing in  the  outer  wall  of  their  unicellular  body,  and  some- 
times a  gullet-tube  as  well.  Besides  this  cell-mouth 
(cytostoma)  we  usually  find  also  a  second  opening  for 
the  discharge  of  indigestible  matter,  a  cell-anus  {cyto- 
pyge). 

Metabolism  in  the  tissue  plants  (metaphyta)  forms  a 
long  gradation  from  very  simple  to  very  complicated 
arrangements.  The  lowest  and  oldest  thallophyta,  es- 
pecially the  simplest  algae,  are  not  far  removed  from  the 
communities  of  protophyta,  and,  like  these,  are  merely 
definitely  grouped  colonies  of  cells.  The  social  cells 
which  form  their  most  rudimentary  tissue  are  quite 
homogeneous,  with  no  differentiation  beyond  that  of  sex. 

219 


THE    WONDERS    OF    LIFE 

The  thallus  or  bed-formation  consists  in  the  simplest 
specimens  of  plain  or  branched  fine  threads,  consisting 
of  rows  or  chains  of  homogeneous  cells  (so  conferva 
among  the  green,  ectocarpus  among  the  brown,  and  cal- 
lithamnion  among  the  red  algae).  Other  algse  (such  as 
the  iilva)  form  thin  leaf -shaped  forms  of  the  thallus,  a 
number  of  homogeneous  cells  lying  side  by  side  along  a 
level.  In  the  larger  algs  compact  tissue-bodies  are 
formed,  in  which  frequently  firmer  rows  of  cells  exhibit 
the  rudiments  of  fibres;  and  the  thallus  divides,  as  in 
the  cormophyta,  into  root,  stalk,  and  leaves.  There  is 
also  a  trophic  differentiation,  the  fibres  undertaking 
special  functions  of  nutrition  (the  conduction  of  the  sap). 
The  same  must  be  said  of  the  mosses  (bryophyta).  Their 
lowest  forms  {ricciadincB)  are  close  akin  to  the  algae; 
the  highest  mosses  (the  mnium  and  polytrichum,  for  in- 
stance) approach  the  cormophyta.  Many  botanists 
comprise  these  lower  plants — algae,  fungi,  and  mosses — 
under  the  title  of  "cell-plants"  (cytophyta),  and  oppose 
the  higher  plants — ferns  and  flowering-plants — to  them 
as  "vascular  plants"  (angiophyta),  because  they  have 
complex  fibres  or  sap  vessels.  This  distinction  has  a 
phylogenetic  significance  similar  to  the  division  between 
coelenteria  and  coelomaria  in  the  animal  kingdom. 

While  most  of  the  cell-plants  either  live  in  the  water 
(algae)  or  are  very  simply  organized  on  account  of  their 
saprophytic  or  parasitic  habits  (fungi),  the  vascular 
plants  mostly  live  on  land,  and  have  to  adapt  themselves 
to  much  more  complicated  conditions.  Their  nutrition 
is  accordingly  distributed  among  different  functions,  and 
special  organs  have  been  evolved  to  discharge  them. 
This  is  equally  true  of  the  crytogam  ferns  (pteridophyta) 
and  the  phanerogam  flowering  plants  (anthophyta).  The 
most  important  later  acquisition  which  distinguishes 
both  groups  from  the  lower  cell-plants  is  the  possession 
of  vascular  or  conducting  fibres.     These  organs  for  con- 

220 


NUTRITION 

ducting  water  pass  through  the  entire  body  of  the  vas- 
cular plant  in  the  shape  of  long  tubes,  formed  by  the 
combination  of  rows  of  cells ;  the  cells  themselves  die 
ofif,  and  their  plasma  content  disappears.  The  stream 
of  water  that  rises  constantly  in  these  tubes  is  taken  up 
by  the  roots,  conducted  by  the  fibres  to  all  parts,  and 
given  of?  (transpiration)  by  the  pores  of  the  leaves.  But 
these  pores  also  serve  for  the  breathing  of  plants,  being 
connected  with  the  air-containing  intercellular  passages; 
through  these  air-spaces,  which  serve  for  the  aeration  of 
the  higher  plant-body,  air  and  moisture  can  enter,  and 
oxygen  be  given  off  in  respiration.  Finally,  many  of 
the  vascular  plants  have  special  glands  that  serve  for 
secretion  (of  oil,  resin,  etc.).  In  the  higher  flowering 
plants  this  division  of  work  among  the  various  digestive 
organs  gives  rise  to  a  very  complicated  apparatus  for 
nutrition.  Among  the  many  remarkable  structures  that 
have  been  developed  in  this  way  by  adaptation  to  special 
conditions  we  may  particularly  note  the  organs  for 
catching  and  digesting  insects  in  the  insect-eating  plants, 
the  European  drosera  and  titricalaria,  and  the  tropical 
nepcnthas  and  dioncea. 

The  long  scale  of  evolutionary  forms  which  we  find 
in  the  tissue  animals  (metazoa)  leads  up  uninterrupted- 
ly from  the  simplest  to  the  most  elaborate  physiological 
functions  and  a  corresponding  morphological  complex- 
ity of  organs.  The  two  principal  divisions  of  the  meta- 
zoa are  chiefly  distinguished  by  the  circumstance  that 
in  the  co^lenteria  one  single  system  of  organs,  the  gastro- 
canal  system,  discharges  the  whole  (or  most  part)  of  the 
partial  functions  of  nutrition;  while  in  the  coelomaria 
they  are  usually  distributed  among  four  different  sys- 
tems of  organs,  each  of  which  is  made  up  of  a  number  of 
organs.  To  an  extent,  we  find  once  more  in  each  great 
division  characteristic  types  of  organization.  How- 
ever,  comparative  ontogeny   teaches  us  that  all  these 

221 


THE    WONDERS    OF    LIFE 

various  structures  have  been  developed  from  one  simple 
fundamental  form,  as  I  have  shown  in  my  theory  of  the 
gastrsea  (1872). 

The  older  research  into  the  origin  of  the  nutritive 
apparatus  in  the  metazoa — especially  its  chief  part,  the 
alimentary  or  gastric  canal — had  led  to  the  erroneous 
belief  that  in  several  groups  of  the  metazoa  it  owed 
its  origin  to  very  different  growth-processes,  and  that 
particularly  in  the  higher  vertebrates  (the  amniotes)  it 
was  a  comparatively  late  product  of  evolution.  On  the 
other  hand,  the  comparative  study  of  the  embryology  of 
the  lower  and  higher  animals  led  me  thirty-four  years 
ago  to  the  opposite  conclusion,  that  a  simple  gastric  sac 
was  the  first  and  oldest  organ  of  all  the  metazoa,  and 
that  all  the  different  forms  of  it  had  been  developed  from 
this  primitive  type.  I  gave  this  view  in  my  Biology  of 
the  Sponges  in  1872;  and  I  developed  and  established  it 
in  my  Studies  of  the  Gastrcea  Theory  in  1873.  In  the 
latter  book  I  also  worked  out  the  important  conclusions 
that  follow  from  this  monistic  reform  of  the  theory  of 
germinal  layers  for  the  phylogenetic  natural  classifica- 
tion of  the  animal  kingdom.  I  began  with  the  con- 
sideration of  the  simplest  sponges  (olynthtis)  and  cnidaria 
{hydra).  The  whole  body  of  these  lowest  and  oldest  of 
the  coelenteria  is  in  essence  nothing  but  a  round,  oval,  or 
cylindrical  gastric  vesicle,  a  digestive  sac,  the  thin  wall 
of  which  consists  of  two  simple  layers  of  cells.  The 
outer  layer  (the  ectoderm  or  skin-layer)  is  the  covering 
layer  of  the  external  skin  (epidermis) ;  it  is  the  instru- 
ment of  sensation  and  movement.  The  inner  layer  of 
cells  (entoderm  or  gastric  layer)  serves  for  nutrition;  it 
clothes  the  simple  cavity  of  the  sac,  which  admits  the 
food  by  its  opening  and  digests  it.  This  opening  is  the 
primitive  mouth  (prostoma  or  blastoporus),  the  inner 
cavity  itself  the  primitive  gut  (progaster  or  archenteron) . 
I  proved  that  there  was  the  same  composition  in  the 

222 


NUTRITION 

young  embryos  or  larvae  of  many  of  the  lower  animals, 
and  showed  that  the  manifold  and  apparently  very 
different  embryonic  form  of  all  the  higher  animals 
may  be  reduced  to  the  same  common  type.  To  this  I 
gave  the  name  of  the  "cup-embryo"  or  gastric  larvae 
(gastrula),  and  concluded,  in  virtue  of  the  biogenetic 
law,  that  it  is  the  palingenetic  reproduction  of  a  cor- 
responding ancestral  form  (the  gastrcca)  maintained 
until  the  present  by  heredity.  It  was  not  until  much 
later  (1895)  that  Monticelli  discovered  a  modern  gas- 
traead  (pcmmatodiscus)  which  corresponds  completely  to 
this  hypothetical  ancestor  (see  the  last  edition  of  my 
Anthropogcny,  fig.  287).  The  simplest  living  forms  of 
the  sponges  (olynthus)  and  the  cnidaria  (hydra)  only 
differ  from  this  hypothetical  primitive  form  of  the 
gastraea  by  a  few  secondary  and  subsequently  acquired 
features. 

The  classes  of  the  lower  animals  which  we  comprise 
under  the  name  coelenteria  (or  coslenterata  in  the  widest 
sense)  generally  agree  in  having  all  the  functions  of 
nutrition  accomplished  exclusively  (or  for  the  most  part) 
by  a  single  system  of  organs,  the  gastro-canal  or  gastro- 
vascular  system.  From  their  common  stem-group,  the 
gastra^ads,  three  different  stems  have  been  evolved — the 
sponges,  cnidaria,  and  platodes.  All  these  coelenteria 
have  three  features  in  common:  (i)  The  gastric  canal 
or  tube  has  only  one  opening — the  primitive  mouth, 
which  serves  at  once  for  admitting  food  and  ejecting 
indigestible  matter;  there  is  no  anus;  (2)  there  is  no 
special  body-cavity  (cooloma)  distinct  from  the  gastric 
tube;  (3)  there  is  also  no  trace  of  a  vascular  system. 
All  cavities  that  are  found  in  these  lower  animals  be- 
sides the  digestive  gut-cavity  are  direct  processes  from 
it  (with  the  exception  of  the  nephridia  in  the  platodes). 

While  the  simple  digestive  gut  is  the  sole  organ  of 
nutrition  in  the  stem-group  of  the   gastraeads,  we  find 

223 


THE    WONDERS    OF    LIFE 

other  structures  co-operating  in  the  rest  of  the  coelenteria. 
The  characteristic  stem  of  the  sponges  is  distinguished 
by  the  piercing  of  the  wall  of  the  gastric  vesicle  with 
several  holes.  Through  these  water  pours  into  the  body, 
bringing  with  it  the  small  particles  of  food  which  are 
received  and  digested  by  the  ciliated  cells  of  the  entoderm ; 
the  water  emerges  again  by  the  mouth-opening  {osculmn). 
The  best-known  of  the  sponges  is  the  common  bath- 
sponge  (euspongia  officinalis),  the  horny  skeleton  of 
which  we  use  daily  in  washing.  In  these  and  most  other 
sponges  the  large,  unshapely  body  is  traversed  by  a 
number  of  branching  canals,  on  which  there  are  thou- 
sands of  tiny  vesicles,  produced  by  the  multiplication 
of  a  simple  gastric  vesicle  of  the  primitive  sponge 
(olynthus).  Each  of  these  ciliated  chambers  is  really  a 
tiny  gastraea,  a  "person"  of  the  simplest  character  {cf. 
chapter  vii.)-  Hence  we  may  regard  the  whole  sponge- 
body  as  a  gastraead-stock  {cormus). 

The  large  group  of  the  cnidaria  offers  a  long  series  of 
evolutionary  stages,  from  very  small  and  simple  to  very 
large  and  elaborate  forms.  Some  of  them  remain  at  a 
very  low  stage,  as  does  our  common  green  fresh-water 
polyp  {hydra  viridis),  which  only  differs  from  the  gastraea 
by  a  few  variations  in  tissue  and  the  formation  of  a 
crown  of  feelers  about  the  mouth.  Most  of  the  polyps 
form  stocks  (cormi),  the  individuals  shooting  out  buds 
which  remain  joined  to  the  mother  animal.  In  these 
and  all  the  other  stock-forming  animals  the  nutrition 
is  communistic ;  all  the  food  that  the  individuals  get  and 
digest  is  conducted  by  tubes  to  the  common  fund  and 
equally  distributed.  In  all  the  larger  cnidaria  the  body- 
wall  becomes  thicker,  and  is  traversed  by  branching 
gastro-canals ;  these  convey  the  nutritive  fluid  to  all 
parts  of  the  body. 

While  the  fundamental  type  in  the  cnidaria  is  radial 
(determined  by  the  crown  of  radiating  feelers  or  tentacles 

224 


NUTRITION 

that  surrounds  the  mouth),  it  is  bilateral-symmetrical  in 
the  platodes  or  "flat-worms"  {plathchiiinthcs).  In  this 
animal-stem,  moreover,  the  lowest  forms,  the  platodaria 
(also  called  cryptocccla  and  accela)  come  very  close  to  the 
gastrsea.  But  most  of  the  platodes  are  distinguished 
from  the  rest  of  the  ca'lenteria  by  the  formation  of  a  pair 
of  nephridia  (renal  canals  or  water-vessels),  thin  tubes 
which,  as  excretory  organs,  remove  from  the  body  the 
unusable  products  of  metabolism,  the  urine.  Here  we 
have  a  second  organ  of  nutrition,  the  gut  tube,  added  to 
the  first.  In  the  lower  platodes  this  remains  very 
simple.  As  a  rule,  a  gullet  tube  (pharynx)  is  formed  by 
the  hollowing  out  of  the  mouth,  as  in  the  corals;  and  as 
in  the  case  of  the  latter  branched  canals,  which  conduct 
the  nutritive  sap  from  the  stomach  to  distant  parts  of  the 
body,  grow  out  of  the  stomach,  in  the  larger  coil-worms 
(turbcllaria)  and  suction-worms  {trcmatodcs).  On  the 
other  hand,  the  gut  atrophies  in  the  tape-worms  {ccs- 
todes) ;  as  these  parasites  live  in  the  intestines  or  other 
organs  of  animals,  they  can  obtain  their  nutritive  sap 
directly  from  them  through  the  surface  of  the  skin. 

The  more  highly  organized  coclomaria  differ  from  the 
simpler  coelenteria  chiefly  by  the  greater  complexity  in 
the  structure  and  functions  of  their  apparatus  of  nu- 
trition. As  a  rule,  these  functions  are  divided  between 
four  groups  of  organs,  which  are  not  yet  differentiated 
in  the  coelenteria  —  namely :  i ,  organs  of  digestion 
(gastric  system);  2,  organs  of  circulation  (vascular 
system);  3,  organs  of  breathing  (respiratory  system); 
and  4,  organs  of  excretion  (renal  system).  Moreover, 
in  the  coclomaria  the  gastric  canal  has  usually  two 
openings,  the  mouth  and  the  anus.  Finally,  they  all 
have  a  special  body-cavity  (cccloma) ;  this  is  quite  separate 
from  the  gastric  canal,  which  is  suspended  in  it,  and 
serves  for  the  formation  of  the  sexual  cells.  It  is 
formed  in  the  embryo  by  the  hollowing  out  and  cutting 
IS  225 


THE    WONDERS    OF    LIFE 

off  of  a  pair  of  sacs  (coelom-pouches)  from  the  gut  near 
the  mouth;  the  pouches  touch,  and  then  coalesce,  as 
their  division  -  walls  break  down.  If  a  part  of  the 
dividing  wall  remains,  it  serves  as  mesentery  to  fasten 
the  gut  to  the  body-wall.  The  action  of  the  four 
groups  of  alimentary  organs  remains  very  simple  in  the 
lowest  and  oldest  coelomaria,  the  worms  {vernialia)\ 
but  in  the  other  higher  animals,  which  have  been 
evolved  from  these,  they  have  very  varied  and  often 
complicated  features. 

In  the  great  majority  of  the  coelomaria  the  gastric 
system  forms  a  highly  differentiated  apparatus,  com- 
posed, as  in  man,  of  a  number  of  different  organs.  The 
food  is  usually  taken  in  by  the  mouth,  ground  up  by  the 
jaws  or  the  teeth,  and  softened  with  saliva,  which  the 
salivary  glands  pour  into  the  cavity  of  the  mouth. 
From  the  mouth  the  pulpy  food  passes  in  swallowing 
into  the  gullet,  which  often  has  glandular  appendages, 
and  from  this  through  the  narrow  esophagus  into  the 
stomach.  This  most  important  part  of  the  alimentary 
apparatus  is  often  divided  into  several  sections,  one  of 
which  (the  masticating  stomach)  is  armed  with  teeth 
and  prepared  for  a  further  triturition  of  solid  pieces, 
while  the  other  (the  glandular  stomach)  produces  the 
dissolving  gastric  juice.  The  liquefied  food  (chylus) 
then  passes  into  the  small  intestine  {ileum),  which  has 
to  absorb  it,  and  is  as  a  rule  the  longest  section  of  the 
alimentary  canal.  A  number  of  different  digestive 
glands  open  into  this  intestine,  the  most  important  of 
them  being  the  liver.  The  small  intestine  is  often 
sharply  distinguished  from  the  large  intestine  (colon), 
the  last  large  section  of  the  alimentary  canal;  into  this 
also  a  number  of  glands  and  blind  intestines  open.  The 
last  portion  of  it  is  called  the  recttmi,  and  this  removes 
the  indigestible  remnants  of  the  food  (fcEces)  through 
the  anus. 

226 


NUTRITION 

This  general  plan  of  the  alimentary  system,  which  is 
common  to  most  of  the  coclomaria  in  its  chief  features, 
is  very  much  modified  in  the  various  groups  of  these 
animals  and  adapted  to  their  several  conditions  of  nu- 
trition. The  simplest  structures  are  found  in  many  of 
the  vermalia;  the  lowest  forms  of  these,  the  rotifers,  and 
especially  the  gastrotricha,  still  closely  resemble  their 
platode  ancestors,  the  turbellaria.  The  higher  type  of 
animal-stems  which  have  been  evolved  from  them  are 
partly  distinguished  by  special  structures.  Thus  the 
mollusks  have  a  characteristic  masticating  apparatus; 
on  their  tongue  there  is  a  hard  plate  (radiila)  armed 
with  a  number  of  teeth,  which  grinds  against  a  hard  up- 
per jaw,  and  so  breaks  up  the  food.  In  most  of  the  ar- 
ticulates this  work  is  done  by  side-jaws,  which  consist 
of  hard  rods  and  represent  modified  bones.  The  verte- 
brates and  the  closely  related  tunicates  are  distinguished 
by  the  conversion  of  the  first  sections  of  the  alimentary 
canal  into  a  characteristic  respiratory  apparatus  (gills). 
But  the  construction  of  the  various  sections  of  the  gastro- 
canal  also  varies  a  good  deal  in  the  small  groups  of  the 
coelomaria,  as  it  depends  to  a  great  extent  on  the  nature 
of  the  food  and  the  conditions  in  which  it  is  got  and 
prepared.  The  largest  expenditure  of  mechanical  and 
chemical  energy  is  needed  for  a  voluminous  solid  vege- 
tal diet.  Hence  the  alimentary  canal  and  its  many 
appendages  are  longest  and  most  complicated  in  the 
plant-eating  snails,  leaf-eating  insects,  and  grass-eating 
ruminants.  On  the  other  hand,  they  are  shortest  and 
simplest  in  parasitic  coelomaria,  which  derive  their  fluid 
food  already  prepared  from  the  contents  of  another  ani- 
mal's intestines.  In  these  cases  the  gut  may  altogether 
atrophy;  as  in  the  acanthoccphala  among  the  vermalia, 
the  entoconcha  among  the  mollusks,  and  the  saccidina 
among  the  Crustacea. 

The  greater  the  extent  of  the  body,  and  the  more 

227 


THE    WONDERS    OF    LIFE 

complex  the  organization  of  the  higher  animals,  the 
more  necessary  it  is  to  have  an  orderly  and  regular  dis- 
tribution of  the  nutritive  fluid  to  all  parts.  In  the 
coelenteria  this  work  is  accomplished  by  the  gastric 
canals  (side  branches  from  the  gut,  opening  into  its 
cavity)  but  in  the  coelomaria  it  is  done  much  better  by 
means  of  blood-vessels  {vasa  sanguijera) .  These  canals 
do  not  communicate  directly  with  the  gastro-canal,  but 
are  formed  independently  of  it  in  the  surrounding  par- 
enchyma of  the  mesoderm.  They  take  up  the  filtered 
and  chemically  improved  food-fluid,  which  transudes 
through  the  intestinal  walls,  and  conduct  it  in  the  form 
of  blood  to  all  parts  of  the  body.  This  blood  generally 
contains  millions  of  cells,  which  are  of  great  importance 
in  metabolism.  The  blood-cells  of  the  lower  coelomaria 
are  usually  colorless  (leucocytes),  while  those  of  the 
vertebrates  are  mostly  red  (rhodocytes). 

The  circulation  of  the  blood  in  most  of  the  coelomaria 
is  effected  by  a  heart,  a  contractile  tube,  formed  by  the 
local  thickening  of  a  skin-vessel,  which  contracts  and 
beats  regularly  by  means  of  its  muscular  bands.  Origi- 
nally two  of  these  skin-vessels  were  developed  in  the 
abdominal  wall — a  dorsal  vessel  in  the  upper  and  ven- 
tral vessel  in  the  lower  wall  (as  in  many  of  the  ver- 
malia).  The  heart  is  formed  from  the  dorsal  vessel  in 
the  moUusks  and  articulates,  but  from  the  ventral  in 
the  tunicates  and  vertebrates.  The  arteries  are  the 
vessels  which  conduct  the  blood  from  the  heart;  those 
which  conduct  it  from  the  body  to  the  heart  are  the 
veins.  The  finest  branchlets  of  both  kinds  of  vessels, 
which  form  the  connecting  link  between  them,  are 
called  capillaries;  these  immediately  effect  the  inter- 
change of  matter  in  the  tissues  by  osmosis.  The  blood- 
vessels co-operate  very  closely  with  the  respiratory 
organs. 

The  interchange  of  gases  in  the  organism,  which  we 

228 


NUTRITION 

call  breathing  or  respiration — the  taking  in  of  oxygen 
and  giving  out  of  carbonic-acid  gas — does  not  require 
special  organs  in  the  lower  animals.  In  these  it  is  ac- 
complished by  epithelial  cells,  which  clothe  the  surface 
of  the  body — the  ectoderm  of  the  outer  skin  layer  and 
the  entoderm  of  the  inner  gut-covering.  As  nearly  all 
these  coelenteria  live  in  the  water,  or  (as  parasites)  in 
some  fluid  that  contains  air,  and  as  these  fluids  are  con- 
stantly pouring  in  and  out  of  the  body,  the  exchange  of 
gases  is  accomplished  at  the  same  time.  But  in  the 
higher  animals  this  is  rarely  found,  only  in  the  small 
animals  of  simple  construction  (such  as  the  rotifers  and 
other  vermalia,  and  the  smallest  specimens  of  the  mol- 
lusca  and  articulata).  The  majority  of  these  coelomaria 
attain  a  considerable  size,  and  so  require  special  organs; 
these  afford  a  larger  surface  for  the  exchange  of  gases  in 
the  limited  space,  and  accomplish  a  very  peculiar  chemi- 
cal work  as  the  localized  organs  of  respiration.  They 
fall  into  two  groups  according  to  the  nature  of  the  en- 
vironment; gills  for  breathing  in  water  and  lungs  for 
breathing  on  land.  The  latter  take  the  oxygen  directly 
from  the  atmosphere,  and  the  former  from  the  water, 
in  which  atmosphere  air  is  contained  in  solution. 

The  instruments  of  water-respiration  which  we  call 
gills  (branchicu)  are  generally  attenuated  parts  or  proc- 
esses of  the  outer  skin  or  the  inner  gastric  skin ;  hence 
we  distinguish  the  two  chief  forms,  external  and  inter- 
nal gills.  Both  are  richly  provided  with  blood-vessels 
which  bring  the  blood  from  the  body  for  the  purpose 
of  aeration.  Cutaneous  or  external  gills  are  especially 
found  in  the  vertebrates,  in  the  form  of  threads,  combs, 
leaves,  pencils,  tufts  of  feathers,  etc.,  which  are  drawn 
out  from  the  entoderm  as  local  processes  of  the  outer 
skin,  and  afford  a  wide  surface  for  the  interchange  of 
gases  between  the  body  and  the  water.  In  the  mollusca 
there  are  usually  a  pair  of  comb-shaped  gills  near  the 

229 


THE    WONDERS    OF    LIFE 

heart;  in  the  articulates  there  are  several  pairs,  repeated 
in  the  different  segments  of  the  body.  Gastric  or  in- 
ternal gills  are  peculiar  to  the  vertebrates  and  the  next- 
related  tunicates,  with  a  small  group  of  the  vermalia, 
the  enteropneusta.  In  these  the  fore-gut  or  head-gut 
is  converted  into  a  gill-organ,  the  wall  of  which  is  pierced 
with  gill-fissures;  the  water  that  has  been  taken  in  by 
the  mouth  passes  away  through  the  outer  openings  of 
these  fissures.  In  the  lower  aquatic  vertebrates  (acrania, 
cyclostoma,  and  fishes)  the  gills  are  the  sole  organs  of 
breathing;  in  the  higher  animals,  that  live  in  the  air, 
they  fall  into  disuse,  and  their  place  is  taken  by  lungs. 
Nevertheless,  heredity  is  so  tenacious  that  we  find  from 
three  to  five  pairs  of  rudimentary  gill-clefts  in  the  em- 
bryo right  up  to  man,  though  they  have  long  since 
ceased  to  have  any  function.  This  is  one  of  the  most 
interesting  of  the  palingenetic  facts  that  prove  the  de- 
scent of  the  amniotes  (including  man)  from  the  fishes. 

The  group  of  the  aquatic  echinoderms  has  some  very 
peculiar  features  of  respiration.  Their  body  possesses 
an  extensive  water-duct,  which  takes  in  the  sea-water 
and  returns  it  by  special  openings  (skin-pores  or  madre- 
porites).  The  many  branches  of  these  water-vessels  or 
ambulacral  vessels  fill  with  water,  especially  the  tiny 
feelers  or  feet,  which  extend  from  the  skin  in  thousands; 
they  serve  at  once  for  movement,  feeling,  and  breathing. 
But  many  of  the  echinoderms  have  also  special  gills — 
the  star-fish  have  small  finger-shaped  cutaneous  gills  on 
the  back,  the  sea-urchins  special  leaf -shaped  ambulacral 
gills,  the  sea-cucumbers  internal  gastric  gills  (tree-shaped 
branching  internal  folds  of  the  rectum). 

The  organs  of  air-breathing  are  called,  in  general, 
lungs  (pulmones).  Like  the  organs  of  water-breathing, 
they  are  formed  sometimes  from  the  external  and  some- 
times from  the  internal  covering  of  the  body.  Cutaneous 
or  external  lungs  are  found  in  several  groups  of  the 

230 


NUTRITION 

vertebrates.  Among  the  mollusks  the  land  -  dwelling 
lung-snails  have  acquired  a  lung-sac  by  change  in  the 
work  of  the  gill  cavity:  among  the  articulata  the  lung- 
spiders  and  scorpions  have  two  or  more  trachea-lungs; 
that  is  to  say,  cutaneous  sacs,  in  which  are  enclosed  fan- 
wise  a  number  of  trachea-leaves.  In  the  other  air- 
breathing  articulates  (tracheata)  we  find,  instead  of 
these  simple  or  branched,  and  often  bushlike,  air-tubes 
(trachecu),  which  spread  through  the  whole  body  and 
conduct  the  air  direct  to  the  tissues.  They  take  the  air 
from  without  by  special  air-holes  in  the  skin  {stigmata 
and  spiracida).  The  myriapods  and  insects  generally 
have  numbers  of  air-holes;  the  spiders  only  one  or  two, 
more  rarely  four,  pairs.  When  these  air-tube  animals 
return  to  an  aquatic  life  (as  happens  with  the  larvae  of 
various  groups  of  insects),  the  outer  air-holes  close  up, 
and  new  thread-shaped  or  leaf-shaped  trachea-gills  are 
formed,  which  take  the  air  from  the  surrounding  water 
by  osmosis.  The  oldest  and  lowest  tracheata  are  the 
primitive  air-tube  animals,  or  protracheata,  and  form  the 
link  between  the  older  annelids  and  the  myriapods. 
They  have  a  number  of  clusters  of  short  air-tubes  dis- 
tributed over  the  whole  skin,  and  it  is  clear  that  these 
have  been  evolved  from  simple  skin-glands  by  change  of 
function. 

Gastric  or  internal  lungs  are  only  found  in  the  higher 
animals,  to  which  we  give  the  name  of  quadrupeds  (or 
tetrapoda),  the  amphibia  and  amniotes,  and  their  fish- 
like ancestors,  the  dipneusta.  These  internal  lungs  are 
sac-shaped  folds  of  the  fore-gut,  formed  originally  from 
the  swimming-bladder  (jiectocystis)  of  the  fishes  by 
change  of  function.  This  air-filled  bladder,  a  sac-shaped 
appendage  of  the  gullet,  merely  serves  the  purpose  of  a 
hydrostatic  organ,  by  varying  the  specific  weight,  in  the 
fishes.  When  the  fish  wishes  to  descend  it  contracts 
the  bladder  and  becomes  heavier;  it  rises  to  the  top  by 

231 


THE    WONDERS    OF    LIFE 

inflating  it  again.  The  lungs  were  formed  by  the  adapta- 
tion of  the  blood-vessels  in  the  wall  of  the  swimming- 
bladder  to  the  interchange  of  gases.  In  the  oldest  living 
lung-fishes  {ceratodtis)  it  is  still  a  simple  sac  {mono- 
pneumones  =  onQ-hingQ6.) ;  in  the  others  the  simple  gullet- 
cavity  divides  early  into  a  pair  of  sacs  {dipnenmoncs, 
two-lunged).  The  wind-pipe  {trachea — not  to  be  con- 
fused with  the  organ  of  the  same  name  in  the  tracheata) 
is  formed  by  the  lengthening  of  their  stalk  and  strength- 
ening of  it  with  cartilaginous  rings.  At  the  anterior  end 
of  the  trachea  we  find  already  formed  in  the  amphibia 
the  larynx,  the  important  organ  of  voice  and  speech. 

The  function  of  removing  unusable  matter  is  not  less 
important  to  the  organism  than  breathing.  Just  as 
breathing  gets  rid  of  the  poisonous  carbonic  acid,  so  the 
kidneys  remove  fluid  and  solid  excreta  in  the  shape  of 
urine;  these  are  partly  acid  (uric  acid,  hippuric  acid, 
etc.),  partly  alkaline  (urea,  guanine,  etc.).  In  most  of 
the  coelomaria  special  organs  for  removing  these  would 
be  superfluous,  as  this  is  accomplished  (like  breathing) 
by  the  stream  of  water  that  is  constantly  passing 
through  the  whole  body.  But  with  the  platodes  we  be- 
gin to  find  important  excretory  organs  in  the  nephridia, 
a  pair  of  simple  and  ramified  canals  which  lie  on  either 
side  of  the  gut,  and  open  outward.  These  primitive 
renal  canals  are  transmitted  by  the  platodes  to  the 
vermalia,  and  by  these  to  the  higher  stems  of  the 
coelomaria.  In  the  latter  they  generally  open  by 
special  funnels  into  the  inner  body-cavity,  which 
serves  as  first  receptacle  for  the  urine.  Their  outer 
opening  sometimes  (primarily)  goes  through  the  outer 
skin  at  the  back  (excretory  pores),  sometimes  (second- 
arily) to  the  rectum,  and  so  out  through  the  anus. 
The  oldest  articulates,  the  annelids,  have  a  pair  of 
nephridia  in  each  segment  of  the  body;  each  renal 
canal,  or  segmental  canal,  consists  of  three  sections,  an 

232 


NUTRITION 

inner  funnel  which  opens  into  the  body-cavity,  a  middle 
glandular  section,  and  an  external  bladder  that  ejects 
the  urine  by  contraction.  The  disposition  of  the  renal 
system  in  the  internally  articulated  vertebrates  is  very 
similar  to  this;  but  now  complicated  structures  begin  to 
appear,  a  pair  of  compact  kidneys  (roics),  which  are 
made  up  of  a  number  of  branching  nephridia.  Three  gen- 
erations of  kidneys  succeed  each  other,  as  phylogenetic 
stages  of  evolution  —  first  the  primary  fore-kidneys 
{protonc pJiros) ,  in  the  middle  the  secondary  primitive 
kidneys  {niesonephros),  and  last  the  tertiary  after- 
kidneys  {metanephros).  The  latter  are  only  reached  in 
the  three  highest  classes  of  vertebrates,  reptiles,  birds, 
and  mammals.  Mollusks  also  have  a  couple  of  compact 
kidneys.  They  are  developed  from  a  pair  of  nephridia, 
the  funnels  of  which  open  internally  into  the  heart- 
pouch  (the  remainder  of  the  reduced  body-cavity); 
at  the  back  they  open  outward.  The  Crustacea  also 
have  generally  a  pair  of  renal  canals.  On  the  other 
hand,  the  protracheata  (the  stem-forms  of  the  air-tube 
animals)  have  segmental  nephridia,  a  pair  to  each  joint 
inherited  from  their  annelid  ancestors.  The  rest  of  the 
tracheata,  the  myriapods,  spiders,  and  insects,  have, 
instead  of  these,  Malpighi  tubes,  funnel-shaped  glands 
that  arise  from  the  entodermal  rectum,  sometimes  one 
pair  or  less,  sometimes  a  number  in  a  cluster. 

While  most  plants  are  purely  plasmodomous,  and 
most  animals  plasmophagous,  there  are  nevertheless  in 
both  organic  kingdoms  a  number  of  species  (especially 
the  lower)  whose  metabolism  has  assumed  peculiar 
forms  by  their  relations  to  other  organisms.  To  this 
class  belong  especially  the  saprosites  and  parasites.  By 
saprosites  are  understood  those  plants  and  animals 
which  feed  entirely  or  mostly  on  the  corpses  of  other 
animals,  or  the  decomposed  matter  which  is  unfit  for 
the  food   of   higher   animals.     Among   the   unicellular 

233 


THE    WONDERS    OF    LIFE 

protists  many  of  the  bacteria,  especially,  belong  to  this 
class,  and  also  many  fungilla  (pJiycomycetes);  among 
the  metaphyta  the  fungi  (mycetes),  and  among  the 
metazoa  the  sponges.  I  have  already  spoken  of  the 
many  peculiarities  of  metabolism  in  the  ubiquitous 
bacteria;  while  many  of  them  cause  putrefaction,  they 
at  the  same  time  feed  on  the  parts  of  other  organisms 
which  have  died.  The  fungi  feed  for  the  most  part  on 
the  decayed  remains  of  plants  and  the  products  of  putre- 
faction which  accumulate  on  the  ground.  In  this 
character  of  scavengers  they  play  the  same  important 
part  on  land  as  the  sponges  do  at  the  bottom  of  the  sea. 
But  a  number  of  small  groups  of  the  higher  plants  and 
animals  have,  as  a  secondary  habit,  turned  to  sapro- 
sitism.  Among  the  metaphyta  we  have  especially  the 
monotropea  (to  which  our  native  asparagus,  nionotropa 
hypopitys,  belongs)  and  many  orchids  (neottia,  coral- 
lorhiza).  As  they  find  their  plasm  directly  in  the 
decayed  matter  in  the  woods,  they  have  lost  their 
chlorophyll  and  green  leaves.  Among  the  metazoa 
many  of  the  vermalia,  and  some  of  the  higher  animals, 
such  as  the  rain-worm  and  many  tube-dwelling  annelids 
(the  mud-eaters,  limicolcE),  etc.,  live  on  putrid  matter. 
The  organs  which  their  nearest  relatives  use  for  obtain- 
ing, breaking  up,  and  digesting  food  (eyes,  jaws,  teeth, 
digestive  glands)  have  been  entirely  or  mostly  lost  by 
these  saprosites.  Many  of  them  form  a  transitional  type 
to  the  parasites. 

By  parasites,  in  the  narrower  sense,  we  understand, 
in  modern  biology,  only  those  organisms  which  live  on 
others  and  derive  their  nourishment  from  them.  They 
are  numerous  in  all  the  chief  divisions  of  the  plant  and 
animal  kingdoms,  and  their  modifications  are  of  great 
interest  in  connection  with  evolution.  No  other  circum- 
stance has  so  profound  an  influence  on  the  organism  as 
adaptation  to  a  parasitic  existence.     Moreover,  there  is 

234 


NUTRITION 

no  other  section  in  which  we  can  follow,  step  by  step, 
the  course  of  the  degeneration  which  is  caused,  and  show 
clearly  the  mechanical  nature  of  the  process.  Hence 
the  science  of  parasites — parasitology — is  one  of  the 
soundest  supports  of  the  theory  of  descent,  and  provides 
an  abundance  of  the  most  striking  proofs  of  the  much- 
contested  inheritance  of  acquired  characteristics. 

Among  the  unicellular  organisms,  the  bacteria  are 
the  most  conspicuous  instances  of  manifold  adaptation 
to  parasitic  habits.  As  we  count  these  unnucleated 
protozoa  among  the  oldest  and  simplest  organisms,  and 
trace  them  directly  by  metasitism  to  the  plasmodomous 
chromacea,  it  is  very  probable  that  they  turned  to  para- 
sitism very  early  in  the  history  of  life.  Even  a  part  of 
the  monera  (in  which  group  we  must  place  the  bacteria 
on  account  of  their  lack  of  a  nucleus)  found  it  conven- 
ient and  advantageous  to  prey  on  other  protists  and  as- 
similate their  plasm  directly,  instead  of  going  through 
the  laborious  process  of  carbon  assimilation  themselves 
in  the  hereditary  fashion.  This  is  also  true  of  the  large 
class  of  the  sporozoa  or  fungilla  {gregarince,  coccidia,  etc.), 
real  nucleated  cells,  which  have  adapted  themselves  in 
various  ways  to  parasitic  habits.  Many  of  them  live  in 
the  rectum,  the  coelum,  or  other  organs  of  the  higher 
animals  (the  gregarinae,  especially  in  the  articulates) ; 
others  in  the  tissues  (for  instance,  the  sarcosporidia  in 
the  muscles  of  mammals,  the  coccidia  and  myxosporidia 
in  the  liver  of  vertebrates).  A  good  many  of  them  are 
"cell-parasites,"  and  live  inside  the  cells  of  other  ani- 
mals, which  they  destroy;  such  are  the  hoemosporidia, 
which  destroy  the  blood-cells  in  man,  and  so  cause  inter- 
mittent fever. 

Among  the  multicellular  metaphyta  it  is  particularly 
the  fungi  that  have  taken  to  parasitism  in  various  ways. 
Many  of  them  are,  as  is  known,  the  most  dangerous 
enemies  of  the  higher  animals  and  plants.     The  various 

235 


THE    WONDERS    OF    LIFE 

species  of  fungi  cause  certain  diseases  by  their  poison- 
ous (chemical)  action  on  the  tissues  of  their  host.  It  is 
well  known  how  our  most  important  cultivated  plants, 
the  vine,  potato,  corn,  coffee,  etc.,  are  threatened  by 
fungoid  diseases;  and  this  is  also  true  of  many  of  the 
lower  and  higher  animals.  It  is  probable  that  the  fungi 
have  been  evolved  polyphyletically  by  metasitism  from 
the  algas. 

Among  the  higher  metaphyta  we  find  parasitism  in 
many  different  families,  especially  orchids,  rhinantha- 
cea  {orobranche,  lathraca),  convolvulacea  {citsciUa),  aris- 
tolochiacea,  loranthacea  (visctim,  loranthus),  rafffesiacea, 
etc.  These  various  kinds  of  flowering-plants  often  grow 
to  resemble  each  other  by  convergence  (that  is  to  say, 
by  their  common  adaptation  to  parasitic  life) ;  they 
lose  their  green  leaves,  the  plasmodomous  chlorophyll 
of  which  is  of  no  further  use  to  them.  Frequently  rudi- 
mentary leaves  are  left  on  them  in  the  form  of  colorless 
scales.  For  the  purpose  of  clinging  to  the  plants  they 
live  on,  and  penetrating  into  their  tissues,  they  evolve 
special  clinging  apparatus  (haustoria,  suctorial  cups, 
creepers).  Their  stalks  and  roots  are  also  modified  in  a 
characteristic  way.  The  whole  productive  force  of  these 
parasites  is  expended  on  their  sexual  organs;  rafflesia 
has  the  largest  flowers  there  are,  more  than  a  yard  in 
diameter. 

Parasitism  in  the  metazoa  (in  all  groups)  is  even  more 
frequent  and  interesting  than  in  the  metaphyta.  The 
mollusks  and  echinoderms  show  the  least  disposition  for 
it,  and  the  platodes,  vermalia,  and  articulates  the  most. 
Even  among  the  gastrasada,  the  common  ancestral  group 
of  the  metaphyta,  we  find  parasites  (kyemaria  and  gas- 
tremaria).  The  protection  they  find  inside  their  hosts 
is  probably  the  reason  why  these  oldest  of  the  metazoa 
have  remained  unchanged  to  the  present  day.  Real 
parasites   are  not  numerous   among  the   sponges   and 

236  / 


NUTRITION 

cnidaria.  But  they  are  very  numerous  among  the 
platodes.  The  suctorial  worms  {trcmatodcs)  Uve  partly 
externally  (as  ectoparasites)  on  other  animals  and  part- 
ly inside  them  (as  endoparasites),  and  produce  serious 
diseases  in  them.  They  have  lost  the  vibratory  coat  of 
their  free-living  ancestors,  the  turbellaria,  and  acquired 
clinging  apparatus  instead.  The  tape-worms  (ccstodes), 
which  live  entirely  in  the  interior  of  other  animals,  and 
are  descended  from  the  suctorial  worms,  have  lost  their 
gastro-canal ;  they  are  nourished  by  imbibition  through 
the  skin.  The  same  degeneration  is  found  in  the  itch- 
worms  (acanthocephala)  among  the  vermalia,  the  para- 
sitic snails  {entoconcha)  among  the  moUusks,  and  the 
root-crabs  {rhizocephala)  amon'g  the  Crustacea. 

The  class  of  Crustacea  affords  the  most  numerous  and 
most  instructive  examples  of  degeneration  through 
parasitism,  because  in  this  class  it  is  found  polyphyleti- 
cally  in  very  different  orders  and  families,  and  because 
their  highly  organized  body  shows  every  stage  of  de- 
generation together  in  the  different  organs.  The  free- 
living  Crustacea  generally  move  about  very  rapidly  and 
ingeniously;  their  numerous  bones  are  well  jointed  and 
excellently  adapted  for  the  most  varied  methods  of  loco- 
motion (running,  swimming,  climbing,  digging,  etc.); 
their  organs  of  sense  are  highly  developed.  As  these 
are  no  longer  used  when  they  take  to  parasitism,  they 
atrophy  and  gradually  disappear.  The  younger  Crustacea 
all  proceed  from  the  same  characteristic  form  of  the 
nauplhis,  and  swim  freely  about;  later,  when  they  settle 
down  to  parasitic  habits,  their  organs  of  sense  and  loco- 
motion atrophy.  As  Fritz  MiiUer-Desterro  showed  in 
his  famous  little  work,  For  Dancin  (1864),  forty  years 
ago,  the  Crustacea  afford  most  luminous  proofs  of  the 
theory  of  descent  and  selection,  and  of  progressive 
heredity  and  the  biogenetic  law.  These  facts  are  the 
more  important  as  the  crab   undergoes   the    same  de- 

237 


THE    WONDERS    OF    LIFE 

generation  by  parasitic  habits  in  a  number  of  different 
orders  and  families. 

From  parasitism  we  must  entirely  distinguish  that 
intimate  life-union  of  two  different  organisms  which  we 
called  symbiosis  or  mutualism.  Here  we  have  an  as- 
sociation of  two  living  things  for  their  mutual  benefit, 
while  the  parasite  lives  entirely  at  the  expense  of  his 
host.  Symbiosis  is  found  among  the  protists,  being 
very  wide-spread  among  the  radiolaria.  In  the  gelati- 
nous envelope  (calymma)  which  encloses  the  central  cap- 
sule of  their  unicellular  bodies  we  find  a  number  of 
motionless  yellow  cells  {zooxanthella)  scattered.  These 
are  protophyta  or  (as  it  is  said)  "unicellular  algae"  of 
the  class  of  paulotomea  {palmcllacea).  They  receive 
protection  and  a  home  from  the  radiolaria,  grow  plas- 
modomously,  and  multiply  by  rapid  segmentation.  A 
large  part  of  the  starch-flour  and  the  plasm  which  they 
form  by  carbon  -  assimilation  goes  as  food  directly  to 
the  radiolarium-host;  the  other  part  of  the  xanthella 
goes  on  growing  and  multiplying.  Similar  yellow  zoo- 
xanthella or  green  zoochlorella  are  found  as  symbionta 
in  the  tissues  of  many  animals.  Our  common  fresh- 
water polyp  {hydra  viridis)  owes  its  green  color  to  the 
zoochlorella  which  live  in  great  numbers  on  the  ciliated 
cells  of  its  entoderm  (the  digestive  gut-epithelium).  In 
general,  however  symbiosis  is  rarer  in  the  metazoa 
than  in  the  metaphyta.  In  the  latter  case  it  is  the 
fundamental  feature  of  a  whole  class  of  plants,  the 
lichens.  Each  lichen  consists  of  a  plasmodomous  plant 
(sometimes  a  protophyte,  sometimes  an  alga)  and  a 
plasmophagous  fungus.  The  latter  affords  a  home, 
protection,  and  water  to  the  green  alga,  which  repays 
the  service  by  providing  food. 


REPRODUCTION 

Reproduction  and  generation — Sexual  and  asexual  reproduction 

—  Superfluous  growth  —  Monogony  —  Self-cleavage  —  Bud- 
ding— Formation  of  spores — Amphigony — Ovum  and  sperm- 
cell — Hermaphrodite  formation  and  separation  of  the 
sexes — Hermaphrodism  and  gonochorism  of  the  cells — 
Monoclinism  and  diclinism — Monoecism  and  dioecism — - 
Alternation  of  sex-division — Sexual  glands  of  the  histona — 
Hermaphroditic  glands — Sexual  ducts — Generative  organs 

—  Parthenogenesis  —  Picdogenesis  —  Metagenesis  —  Hetero- 
genesis  —  Strophogenesis — Hypogenesis — Hybridism — Gen- 
eration of  hybrids  and  the  species — Graduation  of  forms 
of  reproduction. 

WHILE  nutrition  secures  the  maintenance  of  the  or- 
ganic individual,  reproduction  insures  that  of  the 
organic  species,  or  the  group  of  definite  forms  which  we 
distinguish  from  others  by  the  name  "species."  All 
individuals  are  more  or  less  restricted  in  the  duration  of 
their  lives,  and  die  off  after  the  lapse  of  a  certain  time. 
The  succession  of  individuals,  connected  by  reproduc- 
tion and  belonging  to  a  species,  makes  it  possible  for  the 
specific  form  itself  to  last  for  ages.  In  the  end,  how- 
ever, the  species  is  temporary;  it  has  no  "eternal  life." 
After  existing  for  a  certain  period,  it  either  dies  or  is 
converted  by  modification  into  other  forms. 

The  rise  of  new  individuals  by  reproduction  from 
parent  organisms  is  a  natural  phenomenon  with  definite 
time-restriction.  It  cannot  have  continued  from  eter- 
nity on  our  planet,  as  the  earth  itself  is  not  eternal,  and 

239 


THE    WONDERS    OF    LIFE 

even  long  after  its  formation  was  incapable  of  support- 
ing organic  life  on  its  surface.  This  only  became  pos- 
sible when  the  surface  of  the  glowing  planet  had  suffi- 
ciently cooled  for  liquid  water  to  settle  on  it.  Until 
this  stage  carbon  could  not  enter  into  those  combina- 
tions with  other  elements  (oxygen,  hydrogen,  nitrogen, 
and  sulphur)  which  led  to  the  formation  of  plasm.  As 
I  intend  to  deal  with  this  process  of  archigoiiy,  or  spon- 
taneous generation,  in  a  special  chapter,  I  leave  it  for  the 
present,  and  confine  myself  to  the  study  of  tocogony,  or 
parental  generation. 

The  various  forms  of  tocogony,  or  the  reproduction  of 
living  things,  are  generally  divided  into  two  large  groups ; 
on  the  one  hand  there  is  the  simple  form  of  asexual  gen- 
eration (monogony),  and  on  the  other  the  complex  form 
of  sexual  generation  (amphigony).  In  asexual  genera- 
tion the  action  of  one  individual  only  is  needed,  this 
providing  a  product  of  transgressive  (redundant)  growth 
which  develops  into  a  new  organism.  In  sexual  genera- 
tion it  is  necessary  for  two  different  individuals  to  unite 
in  order  to  produce  a  new  being  from  themselves.  This 
amphigony  (or  generatio  digenea)  is  the  sole  form  of  re- 
production in  man  and  most  of  the  higher  animals.  But 
in  many  of  the  lower  animals  and  most  of  the  plants  we 
find  also  asexual  multiplication,  or  monogony,  by  cleav- 
age or  budding.  In  the  lowest  organisms,  the  monera 
and  many  of  the  protists,  fungi,  etc.,  the  latter  is  the 
only  form  of  propagation. 

Strictly  speaking,  monogony  is  a  universal  life-proc- 
ess; even  the  ordinary  cell-cleavage,  on  which  depends 
the  growth  of  the  histona,  is  a  cellular  monogony. 
Hence  historical  biology  must  say  that  monogony  is  the 
older  and  more  primitive  form  of  parental  generation, 
and  that  amphigony  was  secondarily  developed  from 
it.     It  is  important  to  emphasize  this  because,  not  only 

240 


REPRODUCTION 

some  of  the  older  writers,  but  even  some  recent  ones, 
regard  sexual  generation  as  a  universal  function  of  or- 
ganisms, and  declare  that  it  dates  from  the  very  begin- 
ning of  organic  life. 

The  complex  and  frequently  very  intricate  phenomena 
of  sexual  generation,  as  we  hnd  them  in  the  higher  organ- 
isms, become  intelligible  to  us  when  we  compare  them 
with  the  simpler  forms  of  asexual  generation  at  the  low- 
est stages  of  life.  We  then  learn  that  they  are  by  no 
means  unintelligible  and  supernatural  marvels,  but  nat- 
ural physiological  processes,  which,  like  all  others,  may 
be  traced  to  the  action  of  simple  physical  forces.  The 
form  of  energy  which  lies  at  the  root  of  all  tocogony  is 
growth  (crescentia).  And  as  this  phenomenon  is  also 
the  cause,  in  the  form  of  gravitation,  of  the  formation  of 
crystals  and  other  inorganic  individuals,  we  do  away 
with  another  of  the  boundaries  which  people  would  es- 
tablish between  organic  and  inorganic  nature.  Repro- 
duction is  a  kind  of  nutrition  and  growth  of  the  organ- 
ism beyond  the  individual  standard,  building  up  a  part 
of  it  into  a  whole.  This  limit  of  individual  size  is  deter- 
mined for  each  species  by  two  factors — the  inner  con- 
stitution of  the  plasm,  which  is  inherited,  and  the  de- 
pendence on  the  outer  environment,  which  controls 
adaptation.  When  this  limit  has  been  passed, the  trans- 
gressive  growth  takes  the  form  of  reproduction.  Every 
species  of  crystal  has  also  a  definite  limit  of  growth; 
when  this  is  passed,  new  crystal-individuals  are  formed 
in  the  mother-water  on  the  old  individual,  which  grows 
no  further. 

Asexual  or  monogenetic  tocogony  (also  called  "vegeta- 
tive multiplication")  is  always  effected  by  a  single  or- 
ganic individual,  and  so  must  be  traced  to  its  transgres- 
sive  growth.  When  this  affects  the  entire  body  as  a 
total  growth,  the  whole  dividing  into  two  or  more  equal 
parts,  we  call  the  monogenetic  process  division  (or  scg- 
i6  241 


THE    WONDERS    OF    LIFE 

mentation).  But  when  the  growth  is  partial,  and  af- 
fects only  a  part  of  the  individual,  or  when  this  special 
part  separates  from  the  generating  organism  in  the 
form  of  a  bud  (gemma),  the  process  is  called  budding  or 
gemmation  {gemmatio).  Hence  the  essential  difference 
between  the  two  forms  of  generation  is  that  in  division 
the  parent  disappears  in  its  partial  products  (children) ; 
these  are  of  the  same  age  and  form.  But  in  budding 
the  generating  parent  retains  its  individuality;  it  is 
larger  and  older  than  the  young  bud.  This  important 
difference  between  division  and  gemmation,  which  is 
often  overlooked,  holds  good  both  for  protists  (uni- 
cellulars)  and  histona  (multicellulars).  The  fact  that  in 
division  the  individual  as  such  is  destroyed  is  a  sufficient 
refutation  of  Weismann's  theory  of  the  immortality 
of  the  unicellulars.  (See  above,  and  also  the  Riddle, 
chapter  xi.) 

Reproduction  by  division  is  by  far  the  most  common 
of  all  forms  of  propagation.  It  is  the  normal  form  of 
monogony,  not  only  in  many  of  the  protists,  but  also  in 
the  tissue-cells  which  compose  the  tissues  of  the  histona. 
It  is,  moreover,  the  sole  method  of  propagation  for  most 
of  the  monera,  both  chromacea  and  bacteria,  which  are 
in  consequence  often  comprised  under  the  title  of 
"cleavage-plants"  (schizophyta).  Self -cleavage  is  also 
found  among  the  higher  multicellular  organisms — 
namely,  the  cnidaria  (polyps,  medusae).  It  usually  takes 
the  form  of  division  into  two  parts  (dimidiatio  or  hemit- 
omy),  the  body  splitting  into  two  equal  halves.  The 
plane  of  division  is  sometimes  indefinite  (fragmentary- 
cleavage),  sometimes  coincident  with  the  long  axis 
(length-cleavage),  sometimes  with  the  transverse  axis, 
vertical  to  the  long  axis  (transverse-cleavage),  and  less 
frequently  with  a  diagonal  axis  (oblique-cleavage). 
When  the  segmentation  of  a  cell  proceeds  so  rapidly 
that   the   transverse-cleavage   follows   immediately   on 

242 


REPRODUCTION 

the  length-cleavage,  and  the  two  are  at  length  made 
to  coincide,  twofold  division  is  changed  into  fourfold 
division.  And  when  the  process  is  repeated  in  quick 
succession,  and  tlie  body  falls  at  last  into  a  number  of 
small  and  equal  pieces,  we  have  manifold  division  (polyt- 
omy) ;  as  in  the  spore  -  formation  of  the  sporozoa  and 
rhizopoda,  and  in  the  embryonic  sac  of  the  phanerogams. 

Asexual  propagation  by  budding  is  chiefly  distin- 
guished from  segmentation  by  the  fact  that  the  deter- 
mining transgressive  growth  is  only  partial  in  the  one 
and  total  in  the  other.  The  bud  produced  is,  therefore, 
younger  and  smaller  than  the  parent  from  which  it 
issues;  the  latter  may  replace  the  lost  part  by  regenera- 
tion and  produce  a  number  of  buds  simultaneously  or 
successively  without  losing  its  individuality  (whereas 
this  is  destroyed  in  division).  Propagation  by  budding 
is  rare  among  the  protists,  and  more  common  among 
the  histona — that  is,  with  most  of  the  tissue-plants  and 
the  lower,  stock-forming,  tissue-animals  (coelenteria  and 
vermalia).  Most  stocks  (cormi)  are  formed  by  a  sprout 
or  person  shooting  out  buds  which  remain  united  to  it. 
The  layer  and  shoots  of  tissue-plants  are  detached  buds. 
The  two  chief  kinds  of  gemmation  are  terminal  and 
lateral.  Terminal  budding  takes  place  at  the  end  of 
the  long  axis,  and  is  not  far  removed  from  transverse 
division  (for  instance,  the  strobilation  of  the  acraspedae 
medusae  and  the  chain  tape-worms).  Lateral  budding 
is  much  more  common;  it  determines  the  branching  of 
trees  and  generally  of  complex  plants,  and  also  of  the 
tree-shaped  stocks  of  sponges,  cnidaria  (polyps,  corals), 
bryozop,  etc. 

A  third  form  of  asexual  reproduction  is  the  formation 
of  spores  or  "germ-cells,"  which  are  usually  produced 
in  great  numbers  inside  the  organism,  then  detached 
from  it,  and  developed  into  new  organisms  without 
needing  fertilization.     The  spores  are  sometimes  motion- 

24.3 


THE    WONDERS    OF    LIFE 

less  (rest-spores  or  paulospores) ;  sometimes  they  have 
one  or  more  lashes  which  enable  them  to  swim  about 
(rambling  -  spores  or  planospores).  This  monogenetic 
propagation  is  very  common  among  the  protists,  both 
protophyta  and  protozoa.  Among  the  latter  the  sporozoa 
(gregarinae,  coccidia,  etc.)  are  remarkable  for  the  passing 
away  of  the  whole  unicellular  organism  in  the  formation 
of  spores;  in  this  case  and  in  many  of  the  rhizopods 
{mycetozoa)  the  process  coincides  with  manifold  cell- 
division.  In  other  cases  (radiolaria,  thalamophora)  only 
a  portion  of  the  parental  cells  is  used  for  the  production 
of  spores  Spore-formation  is  very  common  among  the 
cryptogams ;  here  it  usually  alternates  with  sexual  prop- 
agation. The  spores  are  generally  formed  in  special 
spore-capsules  (sporangia).  In  the  flowering  plants 
(anthophyta)  sporogony  has  disappeared.  It  is  found 
at  times  in  the  tissue-animals  (in  the  fresh-water  sponges) ; 
in  this  case  the  sporangia  are  called  gemmulcB. 

The  essential  feature  of  sexual  generation  is  the  coa- 
lescence of  two  different  cells,  a  female  ovum  (egg-cell) 
and  a  male  sperm-cell.  The  simple  new  cell  which 
arises  from  the  blending  of  these  is  the  stem-cell  (cytida) , 
the  stem-mother  of  all  the  cells  that  make  up  the  tissues 
of  the  histon.  But  even  among  the  unicellular  protists 
we  find  in  many  places  the  beginnings  of  sexual  differen- 
tiation ;  it  is  foreshadowed  in  the  blending  or  copulation 
of  two  homogeneous  cells,  the  gameta.  We  may  con- 
ceive this  process,  or  zygosis,  as  a  peculiar  and  very 
favorable  kind  of  growth,  that  is  connected  with  a 
rejuvenescence  of  the  plasm;  the  latter  is  enabled  to 
propagate  by  repeated  cleavage  through  the  mixing  of 
the  two  different  plasma-bodies  on  either  side  (am- 
phimixis) .  When  these  two  gameta  become  unequal  and 
differ  in  size  and  shape,  the  larger  female  body  is  called 
the  macrogameton  or  macrogonidion,  and  the  smaller, 
male  part,  the  microgameton  or  microgonidion.   Among 

244 


REPRODUCTION 

the  histona  the  first  is  called  the  egg-cell  {ovttlum),  and 
the  latter  the  sperm-cell  {spcrmiiwi,  or  spermatozoon). 
As  a  rule  the  latter  is  a  very  mobile  ciliated  cell,  the 
former  an  inert  or  amoeboid  cell.  The  vibratory  move- 
ments of  the  sperm-cells  serve  for  approaching  the 
ovulum  in  order  to  fertilize  it. 

The  qualitative  difference  between  the  two  copulating 
sexual  cells  (goiwcyta),  or  the  chemical  difference  be- 
tween the  ovoplasm  of  the  female  and  the  sperm-plasm 
of  the  male  cell,  is  the  first  (and  often  the  only)  condition 
of  amphigony;  subsequently  we  find  in  addition  (in  the 
higher  histona)  a  very  elaborate  apparatus  of  secondary 
structures.  With  this  chemical  difference  is  associated 
a  peculiar  double  form  of  sensitive  perception  and  an 
attraction  based  thereon,  which  is  called  sexual  chemo- 
taxis  or  erotic  chemotropism.  This  "sex-sense"  of  the 
two  gonocyta,  or  elective  affinity  of  the  male  androplasm 
and  the  female  gynoplasm,  is  the  cause  of  mutual  attrac- 
tion and  union.  It  is  very  probable  that  this  sexual 
sense-function,  akin  to  smell  or  taste,  and  the  movements 
it  stimulates,  are  located  in  the  cytoplasm  of  the  two  sex- 
cells,  while  heredity  is  the  function  of  the  caryoplasm  of 
the  nucleus.    (Cf.  the  Antliropogeny,  chapters  vi.  and  vii.) 

The  sexual  difference  between  the  two  forms  of  gono- 
plasm,  the  ovoplasm  of  the  female  and  spermoplasm  of 
the  male  cell,  is  noticeable  at  the  very  beginning  of 
sexual  differentiation  in  the  different  sizes  of  the  cop- 
ulating gameta,  and  later  in  their  increasing  diver- 
gence as  to  shape,  composition,  movement,  etc.  It  leads 
further  to  the  distribution  of  the  germmal  regions  (in 
which  the  sex-cells  are  formed)  into  two  different  in- 
dividuals. When  the  ovum  and  the  sperm-cell  are  pro- 
duced in  one  and  the  same  individual,  we  call  this  an 
hermaphrodite;  and  when  they  are  formed  in  two  dif- 
ferent individuals  (male  and  female),  we  call  them 
monosexual,  or  gonochorists.     In  accordance  with  the 

245 


THE    WONDERS    OF    LIFE 

various  stages  of  individuality  which  we  distinguished 
above  (chapter  vii.),  we  may  indicate  the  following  stages 
of  hermaphrodism  and  gonochorism. 

Some  groups  of  protists,  especially  the  highly  or- 
ganized ciliated  infusoria  (ciliata),  are  distinguished  by 
having  a  separation  of  male  and  female  plasm  within  the 
unicellular  organism.  The  ciliata  propagate,  as  a  rule, 
in  large  numbers  by  repeated  division  (by  indirect  cell- 
cleavage).  But  this  monogony  has  its  limits,  and  has  to 
be  interrupted  from  time  to  time  by  amphigony,  a 
rejuvenation  of  the  plasm,  which  is  effected  by  the 
conjugation  of  two  different  cells  and  the  partial  de- 
struction of  their  nuclear  matter.  By  conjugation  is 
meant  the  partial  and  momentary  union  of  two  different 
unicellulars,  while  copulation  is  a  total  and  permanent 
coalescence.  When  two  ciliated  infusoria  conjugate  they 
place  themselves  side  by  side,  and  connect  for  a  time  by 
means  of  a  bridge  of  plasm.  A  part  of  the  nucleus  of 
each  has  already  divided  into  two  portions,  one  of  which 
functions  as  the  female  standing-nucleus  (paulocaryon) 
and  the  other  as  the  male  travelling-nucleus  (piano- 
caryon).  The  two  mobile  nuclei  enter  the  plasm-bridge, 
and  move  through  it,  pushing  against  each  other,  into 
the  body  of  the  opposite  cell ;  they  then  coalesce  with  the 
deeper  lying  standing-nucleus.  When  a  fresh  nucleus 
has  been  thus  formed  (by  amphimixis)  in  each  of  the 
copulating  cells,  they  again  separate.  The  two  re- 
juvenated cells  have  once  more  acquired  the  power  to 
propagate  for  a  long  time  by  division. 

This  peculiar  hermaphroditic  formation  of  the  cells, 
which  distinguishes  the  ciliated  infusoria  and  some  other 
protists,  and  which  we  now  know  in  its  smallest  details 
through  the  investigations  of  Richard  Hertwig,  Maupas, 
and  others,  is  especially  interesting  because  it  proves 
that  the  chemical  difference  between  the  female  gyno- 
plasm  and  the  male  androplasm  can  be  found  within  a 

246 


REPRODUCTION 

single  cell.  This  erotic  division  of  labor  is  so  impor- 
tant that  formerly  it  was  universally  ascribed  to  two 
different  cells.  Recent  accurate  research,  penetrating 
into  the  smallest  visible  processes  of  fertilization,  has 
shown  that  the  essential  feature  in  the  formation  of  a 
fresh  individual  (the  stem-cell)  is  the  blending  of  equal 
portions  (hereditary  parts)  of  the  male  and  female  nuclei ; 
the  caryoplasm  of  the  two  copulating  cells  is  the  vehicle 
of  heredity  from  the  parents.  The  cytoplasm  of  the 
cell-body,  on  the  other  hand,  serves  the  purposes  of 
adaptation  and  nutrition.  As  a  rule  the  cell-body  of  the 
ovulum  is  very  large,  and  is,  as  a  food-store,  very  richly 
provided  with  albumin,  fat,  and  other  nutritive  matter 
(food-yolk);  while  the  cytoplasm  of  the  sperm-cell  is 
very  small,  and  generally  forms  a  vibrating  lash,  with 
which  it  moves  along  and  seeks  the  ovum. 

In  most  of  the  plants  the  female  and  male  cells  are 
produced  by  the  same  sprout,  and  in  many  of  the  lower 
animals  by  one  and  the  same  person.  This  kind  of 
hermaphrodism  in  "individuals  of  the  second  order"  is 
called  monoclinism  ("one-beddedness").  In  many  of 
the  higher  plants  (monoecic  stocks)  and  most  of  the 
higher  animals  we  have  diclinism  ("  two-beddedness") 
— in  other  words,  the  one  sprout  or  person  has  only  male, 
and  the  other  sprout  or  person  only  female,  organs — this 
is  gonochorism  of  individuals  of  the  second  order.  Mono- 
clinism is  generally  associated  with  sedentary  life  (and 
often  necessary  for  it),  and  diclinism  with  free  movement. 
Adaptation  to  parasitic  habits  also  favors  monoclinism; 
thus,  the  crabs,  for  instance,  are  for  the  most  part 
gonochoristic  individuals,  but  the  creeping  crabs  {cirri- 
pedia),  which  have  adopted  sedentary  (and  to  an  extent 
parasitic)  habits,  have  become  hermaphrodites  in  con- 
sequence. Many  intestinal  parasites  among  the  lower 
animals  (such  as  tape-worms,  suctorial  worms,  wonder- 
snails),  which  live  isolated  lives  inside  other  animals, 

247 


THE    WONDERS    OF    LIFE 

have  to  be  hermaphroditic  and  able  to  fertilize  themselves 
if  the  species  is  to  be  maintained.  On  the  other  hand, 
many  hermaphroditic  flowers,  although  they  have  both 
sorts  of  sex-organs,  are  incapable  of  fertilizing  them- 
selves and  have  to  receive  this  from  insect  visitors  which 
carry  the  pollen  from  one  flower  to  another. 

Individuals  of  the  third  order,  which  we  call  stocks 
cormi)  in  both  the  plant  and  animal  worlds,  also  exhibit 
varying  features  in  the  sex-persons  which  compose  them. 
When  male  and  female  diclinic  sprouts  or  persons  are 
found  side  by  side  on  the  same  stock,  we  call  this  her- 
maphrodism  of  the  cormi  mo;za?aa  ("one-housedness  "); 
this  is  the  case  with  most  of  the  siphonophora  and  some 
of  the  corals.  Dicecia  ("  two-housedness")  is  less  com- 
mon :  in  this  one  stock  has  only  male  and  the  other  only 
female  sprouts  or  persons,  as  in  poplars  and  osiers,  most 
of  the  corals,  and  some  of  the  siphonophora.  The  phys- 
iological advantages  of  crossing — the  union  of  sex-cells 
of  different  individuals — favor  progressive  sex-division 
in  the  higher  organisms. 

A  comparative  study  of  the  features  of  hermaphro- 
dism  and  sex-division  in  the  plant  and  animal  worlds 
teaches  us  that  both  forms  of  sex-activity  are  often 
found  in  closely  related  organisms  of  one  and  the  same 
group,  sometimes  even  in  different  individuals  of  the 
same  species.  Thus,  for  instance,  the  oyster  is  usually 
gonochoristic,  but  sometimes  hermaphroditic;  and  so 
with  many  other  moUusks,  vermalia,  and  articulata. 
Hence,  the  question  often  raised,  which  of  the  two  forms 
of  sex-division  is  original,  is  hardly  susceptible  of  a 
general  answer,  or  without  relation  to  the  stage  of  in- 
dividuality and  the  place  in  classification  of  the  group 
under  discussion.  It  is  certain  that  in  many  cases  her- 
maphrodism  represents  the  original  feature;  for  instance, 
in  most  of  the  lower  plants  and  many  of  the  stationary 
animals    (sponges,    polyps,    platodes,    tunicates,    etc.). 

248 


REPRODUCTION 

Where  we  find  exceptions  in  these  groups,  they  are  of 
secondary  origin.  It  is  equally  certain,  on  the  other 
hand,  that  in  other  cases  the  separation  of  the  sexes  is 
the  primitive  arrangement;  as  in  siphonophorae,  cteno- 
phorae,  bryozoa,  cirripedia,  and  mollusks.  In  these 
cases  the  hermaphrodism  is  clearly  secondary  in  the 
sense  that  the  hermaphrodites  descend  originally  from 
gonochorists. 

It  is  only  in  a  few  sections  of  the  lowest  histona  that 
the  two  kinds  of  sex-cells  arise  without  a  definite  loca- 
tion in  different  parts  of  the  simple  tissue,  as  in  a  few 
groups  of  the  lower  algae  and  in  the  sj^onges.  As  a  rule 
they  are  formed  only  at  definite  positions  and  in  a  special 
layer  of  the  tissue-body,  and  mostly  in  groups,  in  the 
shape  of  sexual  glands  (gonadcs).  These  bear  special 
names  in  different  groups  of  the  histona.  The  female 
glands  are  called  archegonia  in  the  crytogams,  nnccllus 
(formed  from  the  macrosporangia  of  the  pteridophyta) 
in  the  phanerogams,  and  ovaries  in  the  metazoa.  The 
male  glands  are  called  antheridia  in  the  crytogams, 
pollen-sacs  (formed  from  the  microsporangia  of  the 
ferns)  in  the  phanerogams,  and  testicles  (as  spcrmaria) 
in  the  metazoa.  In  many  cases,  especially  in  aquatic 
lower  animals,  the  ovula  (as  products  of  the  ovaries) 
are  discharged  directly  outward.  But,  in  most  of  the 
higher  organisms,  special  sexual  ducts  (i^onodnctus) 
have  been  formed  to  conduct  both  kinds  of  the  gonocyta 
out  of  the  organism. 

While  the  two  kinds  of  sexual  glands  are  usually 
located  in  different  parts  of  the  generating  organism, 
there  are,  nevertheless,  a  few  cases  in  which  the  sex-cells 
are  formed  directly  and  together  from  one  and  the  same 
gland.  These  glands  are  called  hermaphroditic  glands. 
Such  structures  are  very  notable  in  several  highly  dif- 
ferentiated groups  of  the  metazoa,  and  have  clearly 
been  developed  from  gonochoristic  structures  in  lower 

249 


THE    WONDERS    OF    LIFE 

forms.  The  class  of  crested  medusae,  or  ribbed  medusae 
(ctenophorae),  contains  glasslike,  sea-dwelling  cnidaria 
of  a  peculiar  and  complicated  build,  which  probably 
descend  from  hydromedusae  (or  craspedota).  But  where- 
as the  latter  have  very  simple  gonochoristic  structures 
(four  or  eight  monosexual  glands  in  the  course  of  the 
radial  canals  or  in  the  gastric  wall),  in  the  ctenophorae 
the  eight  hermaphroditic  canals  run  in  a  meridian  arch 
from  one  pole  of  the  cucumber-shaped  body  to  the  other. 
Each  canal  corresponds  to  a  ciliary  streamer,  and  forms 
ovaries  at  one  border  and  testicles  at  the  other;  and 
these  are  so  arranged  that  the  eight  intercostal  fields 
(the  spaces  between  the  eight  streamers)  are  alternately 
male  and  female.  Still  more  curious  are  the  hermaph- 
roditic glands  of  the  highly  organized,  land  -  dwelling, 
and  air-breathing  lung-snails  (pulnionata) ,  to  which  our 
common  garden  snail  (arion)  and  vineyard  snail  (helix) 
belong.  Here  we  have  a  hermaphroditic  gland  with  a 
number  of  tubes,  each  of  which  forms  ovaries  in  its 
outer  part  and  sperma  in  the  inner.  Still  the  two  kinds 
of  sex-cells  lead  separately  outward. 

In  most  of  the  lower  and  aquatic  histona  both  kinds 
of  sex-cells,  when  they  are  ripe,  fall  directly  into  the 
water,  and  come  together  there.  But  in  most  of  the 
higher,  and  especially  the  terrestrial,  organisms  special 
exits  or  conducting  canals  have  been  formed  for  the  sex- 
products,  the  sexual  ducts  (gonodtictus) ;  in  the  metazoa 
the  female  have  the  general  name  of  oviducts  and  the 
male  spermaducts  (or  vasa  deferentia).  In  the  vivipa- 
rous histona  special  canals  serve  for  the  conveyance  of 
the  sperm  to  the  ovum,  which  remains  inside  the  moth- 
er's body;  such  are  the  neck  of  the  archegonium  in  the 
cryptogams ,  the  pistil  in  the  phanerogams ,  and  the  vagina 
in  the  metazoa.  At  the  outer  opening  of  these  conduct- 
ing canals  special  copulative  organs  are  developed,  as  a 
rule. 

250 


REPRODUCTION 

When  the  ejected  sex-cells  do  not  directly  encounter 
each  other  (as  in  many  aquatic  organisms),  special 
structures  have  to  be  formed  to  convey  the  fertilizing 
sperm  from  the  male  to  the  female  body.  This  process 
of  copulation  becomes  important,  as  it  is  associated  with 
characteristic  feelings  of  pleasure,  which  may  cause  ex- 
treme psychic  excitement;  as  sexual  love  it  becomes, 
in  man  and  the  higher  animals,  one  of  the  most  powerful 
springs  of  vital  activity.  In  many  of  the  higher  ani- 
mals (namely,  vertebrates,  articulates,  and  mollusks) 
there  are  also  formed  a  number  of  glands  and  other 
auxiliary  organs  which  co-operate  in  the  copulation. 

The  manifold  and  intimate  relations  which  exist,  in 
man  and  the  higher  animals  (especially  vertebrates  and 
articulates),  between  their  sexual  life  and  their  higher 
psychic  activity,  have  given  rise  to  plenty  of  "wonders 
of  life."  Wilhelm  Bolsche  has  so  ably  described  them 
in  his  famous  and  popular  work,  TJie  Life  of  Love  in 
Nature,  that  I  need  only  refer  the  reader  to  it.  I  will 
only  mention  the  great  significance  of  what  are  called 
"secondary  sexual  characters."  These  characteristics 
of  one  sex  that  are  wanting  in  the  other,  and  that  are 
not  directly  connected  with  the  sexual  organs — such  as 
the  man's  beard,  the  woman's  breasts,  the  lion's  mane, 
or  the  goat's  horns — have  also  an  aesthetic  interest;  they 
have,  as  Darwin  showed,  been  acquired  by  sexual  selec- 
tion, as  weapons  of  the  male  in  the  struggle  for  the 
female,  and  vice  versa.  The  feeling  of  beauty  plays  a 
great  part  in  this,  especially  in  birds  and  insects;  the 
beautiful  colors  and  forms  which  we  admire  in  the  male 
bird  of  paradise,  the  humming-bird,  the  pheasant,  the 
butterfly,  etc.,  have  been  formed  by  sexual  selection 
{of.  the  History  of  Creation). 

In  various  groups  of  the  histona  the  male  sex  has 
become  superfluous  in  the  course  of  time;  the  ovula 
develop  without  the  need  of  fertilization.     That  is  par- 

251 


THE     WONDERS     OF     LIFE 

ticularly  the  case  in  many  of  the  platodes  (trematodes) 
and  articulates  (crustacea  and  insects).  In  the  bees  we 
have  the  remarkable  feature  that  it  is  only  decided  at 
the  moment  of  laying  the  egg  whether  it  is  to  be  fertil- 
ized or  not ;  in  the  one  event  a  female  and  in  the  other  a 
male  bee  is  formed  from  it.  When  Siebold  proved  at 
Munich  tiiese  facts  of  miraculous  conception  in  various 
insects,  he  was  visited  by  the  Catholic  archbishop  of  the 
city,  who  expressed  his  gratification  that  there  was  now 
a  scientific  explanation  possible  of  the  conception  of  the 
Virgin  Mary.  Siebold  had,  unfortunately,  to  point  out 
to  him  that  the  inference  from  the  parthenogenesis  of 
the  articulate  to  that  of  the  vertebrate  was  not  valid, 
and  that  all  mammals,  like  all  other  vertebrates,  repro- 
duce exclusively  from  impregnated  ova.  We  also  find 
parthenogenesis  among  the  metaphyta,  as  in  the  chara 
crinita  among  the  algae,  the  antennaria  alpina  and  the 
alchemilla  vulgaris  among  the  flowering  plants.  We  are, 
as  yet,  ignorant  for  the  most  part  of  the  causes  of  this 
lapse  of  fertilization.  Some  light  has  been  thrown  on 
it,  however,  by  recent  chemical  experiments  (the  effect 
of  sugar  and  other  water-absorbing  solutions),  in  which 
we  have  succeeded  in  parthenogenetically  developing 
unfertilized  ova. 

In  the  higher  animals  the  complete  maturity  and 
development  of  the  specific  form  are  requisite  for  repro- 
duction, but  in  many  of  the  lower  animals  it  has  been 
observed  recently  that  ovula  and  sperm-cells  are  even 
formed  by  the  younger  specimens  in  the  larva  stage.  If 
impregnation  takes  place  under  these  conditions,  larvae 
of  the  same  form  are  born.  And  when  these  larvae  have 
afterwards  reached  maturity  and  reproduced  in  this 
form,  we  call  the  process  dissogony  ("double-genera- 
tion"). It  is  found  in  many  of  the  cnidaria,  especially 
the  medusae.  But  if  larvae  propagate  by  unfertilized  ova, 
and  so  reproduce  their  kind  parthenogenetically,   the 

252 


REPRODUCTION 

process  is  known  as  pccdogcncsis  ("young-generation"). 
It  is  found  particularly  in  the  platodes  (treniatodcs)  and 
some  of  the  insects  (larva)  of  cccidomyca  and  other  flies). 

In  a  large  number  of  lower  animals  and  plants  sexual 
and  asexual  generation  regularly  alternate.  Among  the 
protists  we  find  this  alternation  of  generation  in  the 
sporozoa;  among  the  metaphyta  in  the  mosses  and 
ferns;  and  among  the  metazoa  in  the  cnidaria,  platodes, 
tunicates,  etc.  Often  the  two  generations  differ  con- 
siderably in  shape  and  degree  of  organization.  Thus,  in 
the  mosses  the  asexual  generation  is  the  spore-forming 
moss  capsule  {s porogoniiini) ,  while  the  sexual  is  the  moss 
plant  with  stalk  and  leaves  {cithnns).  In  the  case  of  the 
ferns,  on  the  other  hand,  the  latter  is  spore-forming  and 
monogenetic,  while  the  thallus-formed,  simple,  and  small 
fore-germ  {protJialliiim)  is  sexually  differentiated.  In 
most  of  the  cnidaria  a  small  stationary  polyp  is  devel- 
oped out  of  the  ovum  of  the  free-swimming  medusa,  and 
this  polyp,  in  turn,  generates  by  budding  medusas, 
which  reach  sexual  maturity.  In  the  tunicates  (salpa) 
a  sexual  social  form  alternates  with  an  asexual  solitary 
form;  the  chain-salpa  of  the  former  are  smaller  and 
differently  shaped  than  the  large  individual  salpa  of  the 
latter,  which  again  generate  chains  by  budding.  This 
special  form  of  metagenesis  was  the  first  to  be  observed, 
as  it  was  in  1819  by  the  poet  Chamisso,  when  he  sailed 
round  the  world.  In  other  cases  (for  instance,  in  the 
closely  related  doliolmn)  a  sexual  generation  alternates 
with  two  (or  more)  neutral  ones.  The  explanation  of 
these  various  forms  of  alternating  generations  is  given 
in  the  laws  of  latent  heredity  (atavism),  division  of 
labor,  and  metamorphosis,  and  especially  by  the  bio- 
genetic law. 

While  in  real  metagenesis  (alternation  of  generations 
in  the  strict  sense)  the  asexual  generation  propagates  by 
budding    or    spore-formation,    this    is    done    partheno- 

253 


THE    WONDERS    OF    LIFE 

genetically  in  the  cognate  process  of  heterogenesis.  This 
it  is  which,  especially  in  many  of  the  articulates,  causes 
an  immense  increase  of  the  species  in  a  short  time. 
Among  the  insects  we  have  the  leaf -lice  (aphides),  and 
among  the  Crustacea  the  water-fleas  (daphnides),  that 
propagate  in  great  numbers  during  warm  weather  by 
unfertilized  "summer-ova."  It  is  not  until  the  autumn 
that  males  appear  and  fertilize  the  large  "winter-ova"; 
in  the  following  spring  the  first  parthenogenetic  genera- 
tion issues  from  the  winter  eggs.  The  two  heterogenetic 
generations  are  very  different  in  the  parasitic  suctorial 
worms  (trematodes).  From  the  fertilized  ovum  of  the 
hermaphrodite  distoma  we  get  simply  constructed  nurses 
(paedogenetic  larvae),  inside  which  cercaria  are  generated 
from  unfertilized  ova;  these  travel,  and  are  afterwards 
converted  (inside  another  animal)  into  distoma  once 
more. 

I  have  given  {General  Morphology,  chap,  ii.,  p.  104)  the 
name  of  strophogenesis  to  the  complicated  process  of 
cell-reproduction,  which  we  find  in  the  ontogeny  of  most 
of  the  higher  histona,  both  phanerogams  and  ccelomaria. 
In  these  there  is  not  a  real  alternation  of  generations,  as 
the  multicellular  tissue-forming  organism  develops  direct- 
ly from  the  impregnated  ovum.  But  the  process  resem- 
bles metagenesis  in  so  far  as  the  ontogenetic  construction 
consists  itself  in  a  repeated  division  of  the  cells.  Many 
generations  of  cells  proceed  by  cleavage  from  the  one 
stem-cell  (the  impregnated  ovum)  before  two  of  these 
cells  become  sexually  differentiated,  and  form  a  genera- 
tion of  sexual  cells.  However,  the  essential  difference 
consists  in  the  fact  that  all  these  generations  of  cells — in 
the  body  of  both  the  higher  animals  and  the  flowering 
plants — remain  joined  together  as  parts  of  a  single 
bion  (a  unified  physiological  individual);  but  in  the 
alternation  of  generations  each  group  produced  is  made 
up  of  a  number  of  bionta,  which  live  as  independent 

254 


REPRODUCTION 

forms — often  so  different  from  each  other  that  they  were 
formerly  thought  to  be  animals  of  separate  classes,  such 
as  the  polyps  and  medusae.  Hence  we  must  not  describe 
the  reproductive  circle  of  the  phanerogams  as  an  al- 
ternation of  generations,  although  it  has  started  from 
the  fern  (by  abbreviated  heredity). 

All  simple  forms  of  sexual  reproduction  without  alter- 
nation of  generations  are  comprised  under  the  title  of 
hypogenesis.  The  generative  cycle  proceeds  from  ovum 
to  ovum  in  one  and  the  same  bion  or  physiological 
individual.  This  form  of  development  is  usual  with 
most  of  the  higher  animals  and  plants;  it  may  proceed 
with  or  without  metamorphosis.  The  younger  forms 
which  arise  temporarily  in  the  latter  case,  and  are  distin- 
guished from  the  sexually  ripe  form  by  the  possession  of 
the  provisional  (and  subsequently  disappearing)  organs 
— larva  organs  (for  instance,  the  tadpole  or  the  pupa), 
are  comprised  under  the  general  head  of  larvas. 

As  a  rule,  only  organisms  of  the  same  species  seem 
to  have  sexual  union  and  generate  fertile  progeny.  This 
was  formerly  a  rigid  dogma,  and  served  the  purpose  of 
defining  the  loose  idea  of  the  species.  It  was  said: 
"When  two  animals  or  plants  can  have  fertile  offspring 
they  belong  to  the  same  real  species."  This  principle, 
which  once  afforded  support  to  the  dogma  of  the  con- 
stancy of  species,  has  long  been  discarded.  We  now 
know  by  numbers  of  sound  experiments  that  not  only 
two  closely  related  species,  but  even  two  species  of 
different  genera,  may  have  sexual  intercourse  in  certain 
circumstances,  and  that  the  hybrids  thus  generated  can 
have  fertile  offspring,  either  by  union  among  themselves 
or  with  one  of  the  parents.  However,  the  disposition  to 
hybridism  varies  considerably,  and  depends  on  the  un- 
known laws  of  sexual  affinity.  This  sexual  affinity  must 
be  based  on  the  chemical  properties  of  the  plasm  of 
the  copulating  cells,  but  it  seems  to  show  a  good  deal  of 

255 


THE    WONDERS    OF    LIFE 

vagueness  in  its  effect.  As  a  rule,  hybrids  exhibit  a 
combination  of  the  features  of  both  parents. 

It  has  been  proved  by  many  recent  experiments  that 
hybrids  have  a  more  powerful  build  and  can  repro- 
duce more  strongly  than  pure  offspring,  whereas  pure 
selection  has  generally  in  time  an  injurious  effect.  A 
freshening  by  the  introduction  of  new  blood  seems  to  be 
good  from  time  to  time.  Hence,  it  is  just  the  reverse  of 
what  the  former  dogma  of  the  constancy  of  species 
affirmed.  The  question  of  hybridism  has,  generally 
speaking,  no  value  in  defining  the  species.  Probably 
many  so-called  "true  species,"  which  have  relatively 
constant  features,  are  really  only  permanent  hybrids. 
This  applies  especially  to  lower  sea-dwelling  animals,  the 
sexual  products  of  which  are  poured  into  the  water  and 
swarm  together  in  millions.  As  we  know  of  various 
species  of  fishes,  crabs,  sea-urchins,  and  vermalia,  that 
their  hybrids  are  very  easily  produced  and  maintained 
by  artificial  impregnation,  there  is  nothing  to  prevent 
us  from  believing  that  such  hybrids  are  also  maintained 
in  the  natural  state. 

The  short  survey  we  have  made  of  the  manifold 
varieties  of  reproduction  is  sufficient  to  give  an  idea  of 
the  extraordinary  wealth  of  this  world  of  wonders.  When 
we  go  more  closely  into  details  we  find  hundreds  of  other 
remarkable  variations  of  the  process  on  which  the  main- 
tenance of  the  species  depends.  But  the  most  im- 
portant point  of  all  is  the  fact  that  all  the  different 
forms  of  tocogony  may  be  regarded  as  connected  links  of 
a  chain.  The  steps  of  this  long  ladder  extend  uninter- 
ruptedly from  the  simple  cell-division  of  the  protists  to 
the  monogony  of  the  histona,  and  from  this  to  the  com- 
plicated amphigony  of  the  higher  organisms.  In  the 
simplest  case,  the  cell-cleavage  of  the  monera,  prop- 
agation (by  simple  transverse  division)  is  clearly  noth- 
ing more  than  transgressive  growth.     But  even  the  pre- 

256 


REPRODUCTION 

liminary  stage  of  sexual  differentiation,  the  copulation  of 
two  equal  cells  (gamcta),  is  really  nothing  but  a  special 
form  of  growth.  Then,  when  the  two  gameta  become 
unequal  in  the  division  of  labor,  when  the  larger  inert 
macrogameton  stores  up  food  in  itself,  and  the  smaller, 
mobile  microgameton  swims  in  search  of  it,  we  have 
already  expressed  the  difference  between  the  female 
ovum  and  the  male  sperm-cell.  And  in  this  we  have  the 
most  essential  feature  of  sexual  reproduction. 

The  reproduction  of  the  organism  is  often  regarded  as 
a  perfect  mystery  of  life,  and  as  the  vital  function  which 
most  strikingly  separates  the  living  from  the  lifeless. 
The  error  of  this  dualistic  notion  is  clear  the  moment 
one  impartially  considers  the  whole  gradation  of  forms 
of  reproduction,  from  the  simplest  cell-division  to  the 
most  elaborate  form  of  sexual  generation,  in  phylogenetic 
connection.  It  is  obvious  all  through  that  transgressive 
growth  is  the  starting-point  in  the  formation  of  new 
individuals.  But  the  same  must  be  said  of  the  multipli- 
cation of  inorganic  bodies — the  cosmic  bodies  on  the 
larger  scale,  crystals  on  the  smaller  scale.  When  a 
rotating  sun  passes  a  certain  limit  of  growth  by  the 
constant  accession  of  falling  meteorites,  nebulous  rings 
are  detached  at  its  equator  by  centrifugal  force,  and 
form  into  new  planets.  Every  inorganic  crystal,  too, 
has  a  certain  limit  of  individual  growth  (determined  by 
its  chemical  and  molecular  constitution).  However 
much  mother-water  you  add,  this  is  never  passed,  but 
new  crystals  (daughter-crystals)  form  on  the  mother- 
crystal.     In  other  words,  growing  crystals  propagate. 

17 


XII 

MOVEMENT 

Mechanics  as  the  science  of  motion  (kinematics  and  phoron- 
omism)  —  Chemistry  of  vital  movement  —  Active  and 
passive  movements — Undulatory  movement — Mechanism 
of  imbibition — Autonomous  and  reflex  movements — Will 
and  willing — Mixed  movements — Movements  of  growth — 
Direction  of  the  vital  movement — Direction  of  the  crystal- 
lizing force — Direction  of  cosmic  motion — Movements  of 
protists — Amoeboid,  myophenous,  hydrostatic,  secretory, 
vibratory  movements:  cilia  and  lashes — Movements  of 
histona,  metaphyta,  and  metazoa — Locomotion  of  tissue 
animals :  ciliary  motion  and  muscular  movements — Muscles 
of  the  skin — Active  and  passive  organs  of  movement — 
Radiata,  articulata,  vertebrata,  mammalia — Human  move- 
ments. 

ALL  things  in  the  world  are  in  perpetual  motion. 
L  The  universe  is  a  perpetuunt  mobile.  There  is  no 
real  rest  anywhere;  it  is  always  only  apparent  or  relative. 
Heat  itself,  which  constantly  changes,  is  merely  motion. 
In  the  eternal  play  of  cosmic  bodies  countless  suns  and 
planets  rush  hither  and  thither  in  infinite  space.  In 
every  chemical  composition  and  decomposition  the 
atoms,  or  smallest  particles  of  matter,  are  in  motion, 
and  so  are  the  molecules  they  compose.  The  incessant 
metabolism  of  the  living  substance  is  associated  with  a 
constant  movement  of  its  particles,  with  the  building 
up  and  decay  of  plasma-molecules.  But  here  we  must 
disregard  all  these  elementary  kinds  of  movement,  and 
be  content  with  a  brief  consideration  of  those  forms  of 

258 


MOVEMENT 

motion  which  are  peculiar  to  organic  Hfe,  and  a  com- 
parison of  them  with  the  corresponding  motions  of  in- 
organic bodies. 

The  science  of  motion,  or  mechanics,  is  now  taken  in 
very  different  senses:  (i)  in  the  widest  sense  as  a  phi- 
losophy of  life  [generally  called  mechanism  or  mechanic- 
ism  in  England],  equivalent  to  either  monism  or  ma- 
terialism; (2)  in  the  stricter  sense  as  the  physical  science 
of  motion,  or  of  the  laws  of  equilibrium  and  movement 
in  the  whole  of  nature  (organic  and  inorganic);  (3)  in 
the  narrowest  sense  as  part  of  physics,  or  dynamics, 
the  science  of  moving  forces  (in  opposition  to  statics, 
the  science  of  equilibrium;  (4)  in  the  purely  mathemat- 
ical sense  as  a  part  of  geometry,  for  the  mathematical 
definition  of  magnitudes  of  movement;  and  (5)  in 
the  biological  sense  as  phoronomy,  the  science  of  the 
movements  of  organisms  in  space.  However,  these 
definitions  are  not  yet  universally  adopted,  and  there 
is  a  good  deal  of  confusion.  It  would  be  best  to  follow 
the  lead  of  Johannes  Miiller,  as  we  are  going  to  do  here, 
and  restrict  the  name  phoronomy  to  the  science  of  the 
vital  movements  which  are  peculiar  to  organisms,  in 
contrast  to  kinematics,  the  exact  science  of  the  inorganic 
movements  of  all  bodies.  The  real  material  object  of 
phoronomy  is  the  plasm,  the  living  matter  that  forms  the 
material  substratum  of  all  active  vital  movements. 

On  our  monistic  principles  the  inner  nature  of  organic 
life  consists  in  a  chemical  process,  and  this  is  deter- 
mined by  continuous  movements  of  the  plasma-mole- 
cules and  their  constituent  atoms.  As  we  have  already 
considered  this  metabolism  in  the  tenth  chapter,  we 
need  do  no  more  here  than  point  out  that  both  the  gen- 
eral phenomena  of  molecular  plasma-movement  and 
their  special  direction  in  the  various  species  of  plants 
and  animals  can  be  reduced  in  principle  to  chemical  laws, 
and  are  subject  to  the  same  laws  of  mechanics  as  all 

259 


THE    WONDERS    OF    LIFE 

chemical  processes  in  organic  and  inorganic  bodies.  In 
this  we  emphasize  our  opposition  to  vitaUsm,  which  sees 
in  the  direction  of  plasma-movement  the  supernatural 
influence  of  a  mystical  vital  force  or  of  some  ghostly 
"dominant"  (Reinke).  We  agree  with  Ostwald,  who 
also  reduces  these  complex  movements  to  the  play  of 
energy  in  the  plasm — that  is  to  say,  in  the  last  instance 
to  modifications  of  chemical  energy.  In  regard  to  the 
visible  movements  of  the  living  things  which  concern 
us  at  present,  we  must  first  distinguish  passive  and  ac- 
tive, and  subdivide  the  latter  into  reflex  and  autonomous. 
Many  movements  of  the  living  organism  which  the 
inexpert  are  inclined  to  attribute  to  life  itself  are  purely 
passive;  they  are  due  either  to  external  causes  which  do 
not  proceed  from  the  living  plasm,  or  to  the  physical 
composition  of  the  organic  but  no  longer  living  sub- 
stance. Purely  passive  movements,  which  play  an  im- 
portant part  in  bionomy  and  chorology,  comprise  such  as 
the  flow  of  water  and  the  rush  of  the  wind;  they  cause 
considerable  changes  of  locality  and  "passive"  migra- 
tions of  animals  and  plants.  Purely  physical,  again,  is 
what  is  known  as  the  Brownian  molecular  movement 
which  we  observe  with  a  powerful  microscope  in  the 
plasm  of  both  dead  and  living  cells.  When  very  fine 
granules  (for  instance,  of  ground  charcoal)  are  equally 
distributed  in  a  liquid  of  a  certain  consistency,  they  are 
found  to  be  in  a  constant  shaking  or  dancing  movement. 
This  movement  of  the  solid  particles  is  passive,  and  is 
due  to  the  shocks  of  the  invisible  molecules  of  the  fluid 
which  are  continually  impinging  upon  each  other.  In 
the  rhizopods — the  remarkable  protozoa  whose  unicellu- 
lar organism  sheds  so  much  light  on  the  obscure  wonders 
of  life — we  notice  a  curious  streaming  of  the  granules  in 
the  living  plasm.  Within  the  cytoplasm  of  the  amoebae 
particles  travel  up  and  down  in  all  directions.  On 
the   long   thin   plasma-threads    or   pseudopodia   which 

260 


MOVEMENT 

stream  out  from  the  unicellular  body  of  the  radiolaria 
and  thalamophora,  thousands  of  fine  particles  move 
about,  like  promenaders  in  a  street.  This  movement 
does  not  come  from  the  passive  granules,  but  from  the 
active  invisible  molecules  of  the  plasm,  which  are  always 
changing  their  relative  positions.  Thus  also  the  move- 
ments of  the  blood-cells  which  we  can  see  with  the  micro- 
scope in  the  circulation  of  a  young  transparent  fish,  or 
in  the  tail  of  a  frog-larva,  are  not  due  to  the  action  of 
the  blood-cells  themselves,  but  to  the  flow  of  the  blood 
caused  by  the  beat  of  the  heart. 

An  important  factor  in  the  life  of  many  organisms, 
especially  the  higher  plants,  is  the  physical  phenomenon 
called  imbibition;  it  consists  in  the  penetration  of  water 
between  the  molecules  of  solid  bodies  (drawn  to  them 
by  molecular  attraction),  and  the  consequent  displace- 
ment of  the  molecules  by  the  fluid.  In  this  way  the 
volume  of  the  solid  body  is  increased,  and  movements 
are  produced  which  may  have  the  appearance  of  vital 
processes.  The  energy  of  these  imbibitional  bodies  is 
notoriously  very  powerful;  we  can,  for  instance,  split 
large  blocks  of  stone  by  the  insertion  of  a  piece  of  wood 
dipped  in  water.  As  the  cellulose  membrane  of  plant- 
cells  has  this  property  of  imbibition  in  a  high  degree 
(either  in  the  living  or  the  dead  cell),  the  movements  it 
causes  are  of  great  physiological  importance.  This  is 
especially  the  case  when  the  imbibition  of  the  cell  wall 
is  one-sided,  and  causes  a  bending  of  the  cell.  In  con- 
sequence of  the  unequal  strain  in  the  drying  of  many 
fruits,  they  split  open  and  project  their  seeds  to  some 
distance  (as  do  the  poppy,  snap-dragon,  etc.).  The 
moss-capsules  also  empty  their  spores  as  a  result  of  im- 
bibition-curving (in  the  teeth  of  the  openings  of  the 
spore-cases).  The  hygroscopic  points  of  the  heron-bill 
{crodiiim)  curl  up  in  the  dry  state  and  stretch  out  when 
moist;  hence  they  are  used  as  hygrometers  in  the  con- 

261 


THE    WONDERS    OF    LIFE 

stniction  of  meteorological  huts.  The  so-called  "resur- 
rection plants"  {anastatica,  the  rose  of  Jericho,  and 
selaginella  lepidophylla),  which  close  up  like  a  fist  when 
dry,  spread  their  leaves  out  flat  when  moistened  (the 
leaves  imbibing  strongly  on  the  inner  side).  There  is 
no  more  real  case  of  "resuscitation"  (as  many  believe) 
in  these  cases  than  in  the  mythological  resurrection  of 
the  body.  However,  these  phenomena  of  imbibition 
are  not  active  vital  processes;  they  are  independent  of 
the  living  plasm,  and  due  solely  to  the  physical  constitu- 
tion of  the  dead  cell-membranes. 

In  contrast  with  these  passive  movements  of  organ- 
isms, we  have  the  active  movements  which  proceed  from 
the  living  plasm.  In  the  ultimate  analysis,  it  is  true, 
these  may  be  reduced  to  the  action  of  physical  laws  just 
as  well  as  the  passive  movements.  But  the  causes  of 
them  are  not  so  clear  and  obvious;  they  are  connected 
with  the  complicated  chemical  molecular  processes  of  the 
living  plasm,  of  the  physical  regularity  of  which  we  are 
now  fully  convinced,  though  their  complicated  mech- 
anism is  not  yet  understood.  We  may  divide  into  two 
groups  the  many  different  movements,  which  are  called 
vital  in  this  stricter  sense,  and  were  formerly  regarded 
as  evidences  of  the  presence  of  a  mystic  vital  force, 
according  as  the  stimulus  —  the  sensation  of  which  is 
caused  by  the  movement — is  directly  perceptible  or  not. 
In  the  first  case,  we  have  stimulated  (or  reflex  or  para- 
tonic)  movements,  and  in  the  second  voluntary  (auton- 
omous or  spontaneous)  movements.  As  the  will  ap- 
pears to  be  free  in  the  latter,  they  have  been  left  out 
of  consideration  by  many  physiologists,  and  handed  over 
to  the  treatment  of  the  metaphysical  psychologist.  On 
our  monistic  principles  this  is  a  grave  error;  nor  is  it 
improved  when  "  psychonomism "  appeals  to  a  false 
theory  of  knowledge.  On  the  contrary,  the  conscious 
will  (and  conscious  sensation)  is  itself  a  physical  and 

262 


MOVEMENT 

chemical  process  like  unconscious  and  involuntary  move- 
ment (and  unconscious  feeling).  They  are  both  equally 
subject  to  the  law  of  substance.  However,  only  the 
external  stimuli  which  cause  reflex  movements  are 
known  to  us  to  any  great  extent  and  experimentally 
recognizable;  the  internal  stimuli,  which  affect  the  will, 
are  mostly  unknown,  and  are  not  directly  accessible  to 
investigation.  They  are  determined  by  the  compHcated 
structure  of  the  psychoplasm,  which  has  been  gradually 
acquired  by  phylogenetic  processes  in  the  course  of 
millions  of  years. 

The  great  problem  of  the  will  and  its  freedom — the 
seventh  and  last  of  Dubois-Reymond's  world-riddles — 
has  been  dealt  with  fully  in  the  Riddle  (chapter  vii.).  But 
as  we  still  meet  with  the  most  glaring  contradictions 
and  confusion  in  regard  to  this  difficult  psychological 
question,  I  must  touch  upon  it  briefly  once  more.  In 
the  first  place,  I  would  remind  the  reader  that  it  is  best 
to  restrict  the  name  "will"  to  the  purposive  and  con- 
scious movements  in  the  central  nervous  system  of  man 
and  the  higher  animals,  and  to  give  the  name  of  impulses 
(tropisms)  to  the  corresponding  unconscious  processes  in 
the  psychoplasm  of  the  lower  animals,  as  well  as  of  the 
plants  and  protists.  For  it  is  only  the  complicated 
mechanism  of  the  advanced  brain  structure  in  the  higher 
animals,  in  conjunction  with  the  differentiated  sense- 
organs  on  the  one  side  and  the  muscles  on  the  other, 
that  accomplishes  the  purposive  and  deliberate  actions 
which  we  are  accustomed  to  call  acts  of  will. 

But  the  distinction  between  voluntary  (autonomous) 
and  involuntary  (reflex)  movements  is  as  difficult  to 
carry  out  in  practice  as  it  is  clear  in  theory.  We  can 
easily  see  that  the  two  forms  of  movement  pass  into 
each  other  without  any  sharp  boundary  (like  conscious 
and  unconscious  sensation).  The  same  action,  which 
seems  at  first  a  conscious  act  of  the  will  (for  instance,  in 

263 


THE    WONDERS    OF    LIFE 

walking,  speaking,  etc.),  may  be  repeated  the  next 
moment  as  an  unconscious  reflex  action.  Again,  there 
are  many  important  mixed  or  instinctive  movements, 
the  impulse  to  which  comes  partly  from  internal  and 
partly  from  external  stimuli.  To  this  class  belong 
especially  the  movements  of  growth. 

Every  natural  body  that  grows  increases  its  extent, 
fills  a  larger  part  of  space,  and  so  causes  certain  move- 
ments of  its  particles;  this  is  equally  true  of  inorganic 
crystals  and  the  living  organism.  But  there  are  im- 
portant differences  between  the  growth  in  the  two  cases. 
In  the  first  place,  crystals  grow  by  the  external  ap- 
position of  fresh  matter,  while  cells  grow  by  the  intus- 
susception of  fresh  particles  within  the  plasm  (cf.  chapter 
X.).  In  the  second  case,  in  growth,  which  determines 
the  whole  shape  of  the  organism,  two  important  factors 
always  co-operate,  the  inner  stimulus,  which  depends  on 
the  specific  chemical  constitution  of  the  species,  and  is 
transmitted  by  heredity,  and  the  external  stimulus  which 
is  due  to  the  direct  action  of  light,  heat,  gravity,  and 
other  physical  conditions  of  the  environment,  and  is 
determined  by  adaptation  (phototaxis,  thermotaxis, 
geotropism,  etc.). 

A  peculiar  property  of  many  vital  movements  (but 
by  no  means  all)  is  the  definite  direction  they  exhibit; 
these  are  generally  called  purposive  movements.  For 
the  teleologist  they  afford  one  of  the  chief  and  most 
welcome  proofs  of  the  dualistic  theory  of  the  older  and 
the  modern  vitalism.  Baer,  especially,  has  laid  stress 
on  the  purposiveness  of  all  vital  movement.  It  has  been 
given  a  more  precise  expression  recently  by  Reinke. 
His  "dominants"  are  "intelligent  directive  forces,"  es- 
sentially different  from  all  forms  of  energy  or  natural 
forces,  and  not  subject  to  the  law  of  substance.  These 
metaphysical  "vital  spirits"  are  much  the  same  as  the 
immortal   soul   of   dualistic   psychology   or   the   divine 

264 


MOVEMENT 

emanations  of  ancient  theosophy.  They  are  supposed 
not  only  to  regulate  the  special  development  and  con- 
struction of  every  species  of  animal  and  plant,  and  direct 
it  to  a  predetermined  end,  but  also  to  control  all  the 
various  movements  of  the  organism  and  its  organs  down 
to  the  cells.  These  "  hyperenergetic  forces  "  are  equiva- 
lent to  the  "organizing  principle"  and  the  "unconscious 
will"  of  Edward  Hartmann,  the  "arranging  and  con- 
trolling protoplasmic  forces"  of  Hanstein  and  others. 
All  these  metaphysical,  supernatural,  and  teleological 
ideas,  like  the  older  mystic  notion  of  a  special  vital 
force,  rest  on  a  perversion  of  judgment  by  the  apparent 
freedom  of  will  and  purposiveness  of  organization  in 
the  higher  organisms.  These  thinkers  overlook  the  fact 
that  this  purposiveness  can  be  traced  phylogenetically 
to  simple  physical  movements  in  the  lower  organisms. 
Moreover,  they  overlook  or  deny  the  definite  direction 
of  inorganic  forms  of  energy,  though  this  is  just  as 
clear  in  the  origin  of  a  crystal  as  in  the  composition  of 
the  whole  world-structure,  in  the  direction  of  the  mind 
as  in  the  orbit  of  a  planet.  Hence  it  is  important  to 
bear  in  mmd  always  these  two  forms  of  mechanical 
energy,  and  emphasize  their  identity  with  the  direction 
of  vital  movement. 

The  force  of  gravitation  which  is  at  work  in  crystal- 
formation  in  the  simple  chemical  body  exhibits  just 
as  definite  a  direction  as  that  which  appears  in  the  plasm 
in  cell-construction.  In  this  and  other  respects  the 
comparison  of  the  cell  with  the  crystal,  which  was  made 
even  by  the  founders  of  the  cell-theory,  Schleiden  and 
Schwann,  in  1838,  is  thoroughly  justified,  though  it  is 
not  correct  in  some  other  aspects.  When  the  crystal  is 
formed  in  the  mother-water,  the  homogeneous  particles 
of  the  chemical  substance  arrange  themselves  in  a  per- 
fectly definite  direction  and  order,  so  that  mathematical 
planes  of  symmetry  and  axes  arise  within,  and  definite 

265 


THE    WONDERS    OF    LIFE 

angles  at  the  surface.  On  the  strength  of  this,  modern 
crystallography  distinguishes  six  different  systems  of 
crystals.  But,  in  different  conditions,  the  same  sub- 
stance may  crystallize  in  two  or  even  three  different 
systems  (dimorphism  and  trimorphism  of  the  crystal) ; 
thus,  for  instance,  carbonate  of  lime  crystallizes  as  calc- 
spar  in  the  hexagonal,  and  as  arragonite  in  the  rhombic 
system.  If  Reinke  would  be  consistent,  he  ought  to 
postulate  a  "dominant"  for  every  crystal,  to  control  the 
order  and  direction  of  the  particles  in  its  formation.  He 
makes  the  curious  statement  (in  1899)  that  direction  "is 
not  a  measurable  magnitude"  like  energy,  and  so  is  not 
subject,  like  it,  to  the  law  of  substance.  We  can 
mathematically  determine  the  direction  of  the  con- 
structive force  in  the  crystal  just  as  well  as  in  the  cell. 
If  we  comprise  under  the  head  of  cosmokinesis  the 
whole  of  the  movements  of  the  heavenly  bodies  in  space, 
we  cannot  deny  that  they  have  a  definite  direction  in 
detail,  although  our  knowledge  of  this  is  still  very 
incomplete.  We  can  calculate  the  distances  and  speeds 
and  movements  of  the  planets  round  the  sun  with 
mathematical  accuracy;  and  we  gather  from  our  astro- 
nomical observations  and  calculations  that  a  similar 
regularity  prevails  in  the  movements  of  the  other  count- 
less bodies  in  infinite  space.  But  we  do  not  know  either 
the  first  impulse  to  these  complex  movements  or  their 
final  goal.  We  can  only  conclude  from  the  great  dis- 
coveries of  modern  physics,  supported  by  spectrum 
analysis  and  celestial  photography,  that  the  universal 
law  of  substance  on  the  one  side  and  the  law  of  evolution 
on  the  other  control  the  gigantic  movements  of  the 
heavenly  bodies  just  as  they  do  the  living  swarm  of  tiny 
organisms  that  have  inhabited  our  little  planet  for 
milHons  of  years.  Reinke  ought,  consistently,  to  admire 
the  cosmic  intelligence  of  the  Supreme  Being  in  these 
movements  of  the  cosmic  masses  and  its  emanations, 

266 


MOVEMENT 

the  "dominants,"  in  the  actual  direction  of  their  move- 
ments, as  much  as  he  does  in  the  plasma-flow  in  the 
tiny  organism. 

The  manifold  gradation  of  vital  movement  which  we 
find  everywhere  in  the  higher  organisms  is  not  without 
expression  even  in  the  protist  realm.  In  this  respect 
the  chromacea,  the  simplest  forms  of  vegetal  monera, 
and  the  bacteria,  which  we  regard  as  corresponding 
animal  forms,  developed  from  the  former  by  metasitism, 
are  of  great  interest.  As  microscopic  scrutiny  fails  to 
detect  any  purposive  organization  in  these  unnucleated 
cells,  and  it  is  impossible  to  discover  different  organs  in 
their  homogeneous  plasma-body,  we  have  to  look  upon 
their  movements  as  direct  effects  of  their  chemical 
molecular  structure.  But  the  same  must  be  said  also  of 
a  number  of  nucleated  cells,  both  among  the  protoph- 
yta  and  the  protozoa;  only  in  this  case  the  structure 
is  less  simple,  in  so  far  as  both  the  nucleus  itself  and  the 
surrounding  cell-body  exhibit,  in  indirect  division,  com- 
plicated movements  in  the  plasm  (caryokinesis).  Apart 
from  these,  however,  there  is  nothing  to  be  seen  in  many 
unicellular  beings  (e.g.,  paulotomea,  or  calcocytea)  that 
we  need  call  "vital  movement."  On  the  border  between 
the  organic  and  inorganic  worlds  we  have,  as  regards 
movement,  the  simplest  forms  of  the  chromacea,  chroo- 
coccacea.  We  can  see  no  vital  movement  in  these 
structureless  particles  of  plasm  except  slight  changes  of 
form,  which  occur  when  they  multiply  by  cleavage.  The 
internal  molecular  movements  of  the  living  matter, 
which  effect  their  simple  plasmodomous  metabolism  and 
growth,  lie  beyond  our  vision.  The  reproduction  itself, 
in  its  simplest  form  of  self -cleavage,  seems  to  be  merely 
a  redundant  growth,  exceeding  the  limit  of  individual 
size  for  the  homogeneous  plasma  -  globule  {cf.  chapters 
ix.  and  x.). 

The  great  majority  of  the  protists  have  the  appear- 

267 


THE    WONDERS    OF    LIFE 

ance  of  real,  nucleated  cells.  Hence  we  have  to  distin- 
guish two  different  forms  of  movement  in  the  unicellular 
organism — the  inner  movement  in  the  caryoplasm  of  the 
nucleus  and  the  outer  in  the  cytoplasm  of  the  cell-body; 
the  two  enter  into  close  mutual  relations  during  the 
remarkable  process  of  partial  resolution  of  the  nucleus 
(caryolysis).  In  this  modification  and  partial  dissolution 
of  their  constituents  we  observe,  during  indirect  cell- 
division,  certain  complicated  movements  (the  signifi- 
cance of  which  is  as  yet  entirely  unknown),  that  are 
accomplished  by  both  the  granules  of  chromatin  and  the 
threads  of  achromin,  and  which  are  comprised  under  the 
head  of  nuclear  movements  (caryokinesis).  It  has  lately 
been  attempted  to  explain  them  on  purely  physical 
principles.  The  same  may  be  said  of  the  internal  flow 
of  the  plasm  which  we  find  in  the  plasmodia  of  the 
amoebae  and  mycetozoa,  and  in  the  endoplasm  of  many 
of  the  protophyta  and  protozoa 

The  slow  displacement  of  the  molecules  of  plasm 
which  is  at  the  bottom  of  these  plasma-movements  also 
causes  a  variety  of  external  changes  of  form  in  simple 
naked  cells.  Variable  processes  like  folds  or  fingers 
(the  "fold-feet,"  lobopodia)  appear  on  their  surface.  As 
they  are  best  observed  in  the  common  amoebae  (naked 
nucleated  cells  of  the  simplest  kind),  they  are  called 
amoeboid  movements.  With  these  is  connected  the 
variable  movement  of  the  larger  rhizopods,  the  radiolaria 
and  thalamophora,  in  which  hundreds  of  fine  threads 
radiate  from  the  surface  of  the  naked  plasma-body.  A 
number  of  recent  experts  on  the  rhizopods,  such  as 
Biitschli,  Richard  Hertwig,  Rhumbler,  and  others,  have 
attempted  to  trace  to  purely  physical  causes  this  vary- 
ing formation  of  pseudopodia,  and  their  branching  and 
netlike  structure  (without  definite  direction). 

It  is  more  difficult  to  do  this  in  the  case  of  the  most 
highly    differentiated    of    the    protozoa,    the    infusoria. 

268 


MOVEMENT 

With  these  the  free  movement  of  the  unicellular  pro- 
tozoon  is  farther  advanced  through  the  formation  of 
permanent  hairlike  processes  (long  single  lashes  in  the 
flagellata,  and  a  number  of  short  lashes  in  the  ciliata) 
on  the  cell-surface  and  the  movement  of  these  by  con- 
traction and  expansion,  like  the  limbs,  tentacles,  and 
bones  of  the  higher  animals.  The  apparent  spontaneity 
and  various  modulation  in  the  ever-changing  move- 
ments of  these  cell-feet  is,  in  many  of  the  infusoria, 
so  like  the  autonomous  voluntary  movements  in  the 
metazoa  that  several  experts  on  the  infusoria  have  been 
moved  on  this  account  to  ascribe  individual  (and  even 
conscious)  souls  to  them.  Hence  the  difference  be- 
tween the  various  kinds  of  living  movement  is  already 
very  considerable  before  we  leave  the  kingdom  of  the 
protists.  On  the  one  hand,  the  lowest  monera  (chro- 
macea)  join  on  directly  to  inorganic  phenomena.  On 
the  other  hand,  the  highly  differentiated  infusoria 
(ciliata)  show  so  great  a  resemblance  to  the  higher 
animals  in  their  dift'erentiated  and  autonomous  move- 
ments that  they  have  been  credited  with  the  possession 
of  "free-will."  There  is  no  such  thing  as  a  sharp  division. 
In  a  large  section  of  the  higher  protozoa  differentiated 
organs  of  movement  are  developed,  which  may  be  com- 
pared to  the  muscles  of  the  metazoa.  In  the  cytoplasm 
threadlike,  contractile  structures  are  formed,  and  these 
have,  like  the  muscular  fibres  of  the  metazoa,  the  power 
to  contract  and  expand  again  in  definite  directions. 
These  myophaena  or  myonema  form,  in  many  of  the 
infusoria,  both  ciliata  and  flagellata,  a  special  thin 
layer  of  parallel  or  crossed  fibres  underneath  the  exo- 
plasm  or  the  hyaline  skin-layer  of  the  cell.  The  metab- 
olic body  of  the  infusorium  may  be  altered  in  various 
ways  by  the  autonomous  contraction  of  these.  Special 
instances  of  these  myophaena  are  the  myopJirisca  of  the 
acantharia  —  contractile    threads   which   surround    the 

269 


THE    WONDERS    OF    LIFE 

radial  needles  of  these  radiolaria  like  a  crown.  They 
are  found  in  their  outer  gelatine  envelope,  the  calymma, 
and  by  their  contraction  extend  it,  and  so  lessen  the 
specific  gravity. 

Many  of  the  aquatic  protophyta  and  protozoa  have 
the  power  of  autonomous  and  independent  locomotion, 
and  this  often  has  the  appearance  of  being  voluntary. 
Among  the  simplest  fresh-water  protozoa  are  the  arcel- 
lina  or  thecolobosa  {difjittgia,  arcella),  little  rhizopods 
that  are  distinguished  from  the  naked  amoebae  by  the 
possession  of  a  firm  envelope.  They  usually  creep  about 
in  the  slime  at  the  bottom,  but  in  certain  circumstances 
rise  to  the  surface  of  the  water.  As  Wilhelm  Engel- 
mann  has  shown,  they  accomplish  this  hydrostatic  move- 
ment by  means  of  a  small  vesicle  of  carbonic  acid,  which 
expands  their  unicellular  body  like  an  air-balloon;  the 
specific  weight  of  the  cell-body,  which  is  of  itself  heavier 
than  water,  is  sufficiently  lowered  by  this.  The  same 
method  is  followed  by  the  pretty  radiolaria  which  live 
floating  (as  plankton)  at  various  depths  of  the  sea. 
Their  unicellular  (originally  globular)  body  is  divided 
by  a  membrane  into  a  firm  inner  central  capsule  and  a 
soft  outer  gelatine  covering.  The  latter,  known  as  the 
calymma,  is  traversed  by  a  number  of  water- vesicles  or 
vacuoles.  As  a  result  of  an  osmotic  process,  carbonic 
acid  may  be  secreted  or  pure  water  (without  the  salt  of 
the  sea-water)  be  imbibed  in  these  vacuoles;  by  this 
means  the  specific  gravity  of  the  cell  is  lessened,  and  it 
rises  to  the  surface.  When  it  desires  to  make  itself 
heavier  and  sink,  the  vacuoles  discharge  their  lighter 
contents.  These  hydrostatic  movements  of  the  radio- 
laria (for  which  the  myophrisca,  still  more  complicated 
structures,  have  been  developed  in  the  acantharia)  at- 
tain by  simple  means  the  same  end  that  is  accomplished 
in  the  siphonophora  and  fishes  by  air-filled  and  volun- 
tarily contractile  swimming-bladders. 

270 


MOVEMENT 

Numbers  of  the  unicellulars  alter  their  position  very 
characteristically  by  secreting  a  thick  mucus  at  one  side 
of  their  body  and  fastening  this  to  the  ground.  If  the 
secretion  continues,  a  longish  jelly-like  stalk  is  produced 
by  which  the  cell  slowly  pushes  itself  along,  like  a  boat 
with  a  rowing-pole.  This  secretory  locomotion  is  found, 
among  the  protophyta,  in  the  desmidiacea  and  diatomes, 
and  in  some  of  the  gregarinae  and  rhizopods  among  the 
protozoa.  The  peculiar  rolling  movements  of  the  os- 
cillaria  (threadlike  chains  of  blueish-green  unnucleated 
cells,  closely  related  to  the  chromacea)  are  also  effected 
by  the  secretion  of  mucus.  On  the  other  hand,  it  is 
probable  that  the  sliding  movements  of  many  of  the 
diatomes  are  due  to  fine  processes  (vibratory  hairs?)  in 
the  plasm,  which  proceed  either  out  of  the  seams  (raphe) 
of  the  bivalvular  silicious  shells  or  through  the  fine  pores 
in  them. 

Especially  important  in  the  easy  and  rapid  locomotion 
of  many  unicellulars  is  the  formation  of  fine  hairlike 
processes  at  the  surface  of  the  body;  in  the  broadest 
sense,  they  are  called  vibratory  hairs.  If  only  a  few 
whiplike  threads  are  formed,  they  are  called  whips 
(flagella);  if  many  short  ones,  lashes  (cilia).  Flagelli- 
form  movement  is  found  in  some  of  the  bacteria,  but 
especially  in  the  mastigophorous  "whip-infusoria,"  in 
the  mastigota  among  the  protophyta,  and  the  flagellata 
among  the  protozoa.  As  a  rule,  we  have  in  these  cases 
one  or  two  (rarely  more)  long  and  very  thin  whip- 
shaped  processes,  starting  from  one  pole  of  the  long  axis 
of  the  oval,  round,  or  long  cell-body.  These  whips 
(flagella)  are  set  in  vibratory  motion  (apparently  often 
voluntary)  in  various  ways,  and  serve  not  only  for  swim- 
ming or  creeping,  but  also  for  feeling  and  securing  food. 
Similar  whip-cells  (cclluhc  flagcllatcc)  are  also  found  very 
commonly  in  the  body  of  tissue-animals,  usually  packed 
together  in  an  extensive  layer  at  the  inner  or  outer  sur- 

271 


THE    WONDERS    OF    LIFE 

face  (ciliated  epithelium).  If  single  cells  are  released 
from  the  group,  they  may  live  independently  for  some 
time,  continuing  their  movements  and  resembling  free 
infusoria.  The  same  may  be  said  of  the  travelling  spores 
of  many  of  the  algae,  and  of  the  most  remarkable  of  all 
ciliated  cells — the  spermia  or  spermatozoa  of  plants  and 
animals. 

As  a  rule  they  are  cone-shaped,  having  an  oval  or 
pear-shaped  (though  often  also  rod-shaped)  head,  which 
tapers  into  a  long  and  thin  thread.  When  their  lively 
movements  were  first  noticed  in  the  male  seminal  fluid 
(each  drop  of  which  contains  millions  of  them)  two  hun- 
dred years  ago,  they  were  thought  to  be  real  indepen- 
dent animalcules,  like  the  infusoria,  and  so  obtained  their 
name  of  seed-animals  (spermatozoa).  It  was  a  long  time 
(sixty  years  ago)  before  we  learned  that  they  are  de- 
tached glandular  cells,  which  have  the  function  of  fer- 
tilizing the  ovum.  It  was  discovered  at  the  same  time 
that  similar  vibratory  cells  are  found  in  many  of  the 
plants  (algae,  mosses,  and  ferns).  Many  of  the  latter 
(for  instance,  the  spermatozoids  of  the  cycadea)  have, 
instead  of  a  few  long  whips,  a  number  of  short  lashes 
(cilia),  and  resemble  the  more  highly  developed  ciliated 
infusoria  (ciliata). 

The  ciliary  movement  of  the  infusoria  is  held  to  be  a 
more  perfect  form  of  vibratory  movement,  because  the 
many  short  lashes  found  on  them  are  used  for  different 
purposes,  and  have  accordingly  assumed  different  forms 
in  the  division  of  labor.  Some  of  the  cilia  are  used  for 
running  or  swimming,  others  for  grasping  or  touching, 
and  so  on.  In  social  combinations  we  have  the  ciliated 
cells  of  the  ciliated  epithelium  of  the  higher  animals — 
for  instance,  in  the  lungs,  nostrils,  and  oviducts  of  verte- 
brates. 

In  the  unicellular,  non-tissue  forming  protists,  all  the 
vital  movements  seem  to  be  active  functions  of  the  plasm 

272 


MOVEMENT 

of  the  single  cell;  but  in  the  histona,  the  multicellular 
tissue-forming  organisms,  they  are  the  outcome  of  the 
combined  movements  of  the  many  cells  which  compose 
the  tissue.  Careful  anatomic  study  and  experimental 
physiological  scrutiny  of  the  motor  processes  are,  there- 
fore, first  directed,  in  the  case  of  the  histona,  to  clearing 
up  the  nature  and  activity  of  the  special  cells  which  com- 
pose the  tissue,  and  then  the  structure  and  functions  of 
the  tissue  itself.  When  we  start  from  this  point,  and 
survey  the  manifold  active  motor  phenomena  of  the 
histona  as  a  whole,  we  see  at  once  an  essential  agree- 
ment in  the  phoronomy  of  the  two  kingdoms  of  the 
metaphyta  and  metazoa,  in  the  sense  that  at  the  lower 
stages  the  chemical  and  physical  character  of  the  motor 
processes  can  be  clearly  shown  and  can  be  traced  to  an 
interchange  of  energy  in  the  plasm  of  the  cells  that  make 
up  the  tissue.  In  the  higher  stages,  however,  we  find 
striking  differences,  the  voluntary  character  of  many 
autonomous  movements  being  very  conspicuous  in  the 
higher  animals,  and  thus  the  great  problem  of  the  free- 
dom of  the  will  is  added  to  the  purely  physiological 
questions  of  stimulated  movement,  growth-movement, 
etc. 

Moreover,  the  movements  of  the  metazoa  are  much 
more  varied  and  complicated  than  those  of  the  metaph- 
yta, in  consequence  of  the  higher  differentiation  of 
their  sense-organs  and  the  centralization  of  their  ner- 
vous system.  The  former  have  generally  free  locomotion 
and  the  latter  not.  The  special  mechanism  of  the  or- 
gans of  movement  is  also  very  different  in  the  two 
groups.  In  most  of  the  metazoa  the  chief  motor  organs 
are  the  muscles,  which  have  developed  in  the  highest 
degree  the  power  of  definitely  directed  contraction  and 
expansion.  In  most  of  the  metaphyta,  on  the  other 
hand,  the  chief  part  of  the  movements  depend  on  the 
strain  of  the  living  plasm,  or  what  is  called  the  turgor 
z8  273 


THE    WONDERS    OF    LIFE 

or  expansibility  of  the  plant-cells.  This  is  effected  by 
the  osmotic  pressure  of  the  internal  cell-fluid  and  the 
elasticity  of  the  cellulose  wall,  which  is  thus  expanded. 
Nevertheless,  in  both  cases — and  in  all  "vital"  phenom- 
ena— the  real  cause  of  the  process  is,  in  the  ultimate 
analysis,  the  chemical  play  of  energy  in  the  active  plasm. 

The  metaphyta,  with  few  exceptions,  are  fixed  in  one 
spot  for  life,  or  only  mobile  for  a  short  time  when  they 
are  young.  In  this  they  resemble  the  lower  metazoa, 
the  sponges,  polyps,  corals,  bryozoa,  etc.  They  have 
not  free  locomotion.  The  motor  phenomena  which  we 
find  in  them  affect  only  special  parts  or  organs.  They 
are  mostly  reflex  or  paratonic,  and  due  to  external 
stimuli.  Only  a  few  of  the  higher  plants  exhibit  autono- 
mous or  spontaneous  movement,  the  stimulating  cause 
of  which  is  unknown  to  us,  and  which  may  be  compared 
to  the  apparently  voluntary  actions  of  the  higher  ani- 
mals. The  lateral  feather-leaves  of  an  Indian  butter- 
fly flower  {hedysarmn  gyrans)  move  in  circles  through 
the  air,  like  a  pair  of  arms  swinging,  without  any  exter- 
nal cause ;  they  complete  a  circle  in  a  couple  of  minutes. 
Variations  in  the  intensity  of  light  have  no  effect  on 
them.  Similar  spontaneous  movements  of  the  leaves 
of  several  species  of  clover  (trifolium)  and  sorrel  {oxalis) 
are  performed  only  in  the  dark,  not  in  the  light.  The 
terminal  leaf  of  the  meadow-clover  repeats  its  rotation, 
which  describes  more  than  one  hundred  and  twenty  de- 
grees of  an  arc,  every  two  to  four  hours.  The  mechani- 
cal cause  of  these  spontaneous  "variation  movements" 
seems  to  lie  in  variations  of  expansibility. 

Voluntary  and  autonomous  turgescence-movements 
of  this  kind  are  only  observed  in  a  few  of  the  higher 
plants,  but  stimulated  movements  that  are  accomplish- 
ed by  the  same  mechanism  are  very  common  in  the 
vegetal  world.  We  have,  especially,  the  well  -  known 
"sleep,"  or  nyktitropic  movements,  of  many   plants. 

274 


MOVEMENT 

Many  leaves  and  flowers  hold  themselves  vertically  to 
the  streaming  rays  of  the  sun.  When  darkness  comes 
on  they  contract,  and  the  calices  of  the  flowers  close. 
Many  flowers  are  open  for  only  a  few  hours  a  day.  The 
mechanism  of  turgescence,  which  effects  these  swelling 
movements,  consists  in  the  co-operation  of  the  osmotic 
pressure  of  the  internal  cell-fluid  and  the  elasticity  of 
the  strained  cell-membrane  enclosing  the  cytoplasm. 
The  strain  of  the  outer  cellulose  membrane  on  the  plas- 
matic primordial  sac  within  it  grows  so  much  on  the 
accession  of  osmotically  active  matter  that  the  internal 
pressure  is  equal  to  several  atmospheres,  and  the  elastic 
strained  membrane  stretches  from  ten  to  twenty  per 
cent.  When  water  is  withdrawn  again  from  one  of 
these  swollen  or  turgescent  cells,  the  membrane  con- 
tracts; the  cell  becomes  smaller,  and  the  tissue  looser. 
Other  stimuli  besides  light  (heat,  pressure,  electricity) 
may  produce  these  expansional  variations,  and,  as  a 
consequence  of  it,  certain  reflex  movements  (or  para- 
tonic  variational  movements).  The  most  striking  and 
famihar  examples  are  the  flesh-eating  fly-trap  {dioncea 
musciptila)  and  the  sensitive  plant  {mimosa  pudica); 
their  contraction  is  caused  by  mechanical  stimuli,  shak- 
ing, pressure,  or  the  touching  of  the  leaves. 

Most  of  the  higher  animals  have  the  power  of  free  and 
voluntary  locomotion.  It  is,  however,  wanting  in  some 
of  the  lower  classes,  which  spend  the  greater  part  of 
their  life  at  the  bottom  of  the  water,  like  plants.  Hence 
these  were  formerly  held  to  be  vegetable — thus  the 
sponges,  polyps,  and  corals  among  the  coelenteria.  A 
number  of  classes  of  the  coelomaria  have  also  adopted 
the  stationary  life,  such  as  the  bryozoa  and  the  spiro- 
branchia  among  the  vermalia,  many  mussels  (oysters, 
etc.),  the  actinia  among  the  tunicates,  the  sea-lilies 
(crinoidea)  among  the  echinoderms,  and  even  higlily 
organized  articulata,  such  as  the  tube-worms  (tubicolcu), 

275 


THE    WONDERS    OF    LIFE 

among  the  annelids,  and  the  crawHng  crabs  {cirripedia), 
among  the  Crustacea.  All  these  stationary  metazoa 
move  freely  in  their  youth,  and  swim  about  in  the  water 
as  gastruke,  or  in  some  other  larva  form.  They  have 
taken  only  gradually  to  stationary  habits,  and  have  been 
considerably  modified,  and  often  greatly  degenerated,  in 
consequence;  for  instance,  in  the  loss  of  the  higher 
sense-organs,  the  bones,  and  even  of  the  whole  head. 
Arnold  Lang  has  shown  this  very  clearly  in  his  excellent 
work  on  the  influence  of  stationary  life  on  animals. 
The  study  of  these  retrogressive  metamorphoses  is  very 
important  for  the  theory  of  progressive  heredity  and 
selection;  it  also  shows  the  great  value  of  free  locomo- 
tion for  the  higher  sensitive  and  intellectual  develop- 
ment of  the  animals  and  man. 

In  many  of  the  lower  aquatic  metazoa  the  surface  of 
the  body  is  covered  with  vibratory  epithelium — that  is 
to  say,  with  a  layer  of  skin-cells  which  bear  either  one 
long  whip  (fiagellum)  or  several  short  lashes  (cilia). 
Flagellated  epithelium  is  especially  found  in  the  cnidaria 
and  platodes ;  ciliated  epithelium  mostly  in  the  vermalia 
and  mollusca.  As  the  lashing  motion  of  these  hairlike 
processes  brings  a  constant  stream  of  fresh  water  to  the 
surface  of  the  body,  they  first  of  all  effect  respiration 
through  the  skin.  But  in  many  of  the  smaller  metazoa 
they  also  serve  the  purpose  of  locomotion,  as  in  the 
gastraeads,  the  turbellaria,  the  rotifera,  the  nemertina, 
and  the  young  larvae  of  many  other  metazoa.  The 
vibratory  apparatus  reaches  its  highest  development  in 
the  ctenophora.  The  extremely  delicate  and  soft  body  of 
these  gherkin-shaped  cnidaria  swims  slowly  in  the  water 
by  means  of  the  strokes  of  thousands  of  tiny  oar-blades. 
They  are  arranged  in  eight  longitudinal  rows  which 
stretch  from  the  mouth  to  the  opposite  pole.  Each  oar- 
blade  consists  of  the  long  hair-lashes  of  a  group  of 
epithelial  cells  glued  together. 

276 


MOVEMENT 

The  chief  motor  organs  in  the  metazoa  are  the  muscles 
which  constitute  the  "flesh"  of  the  body.  Muscular 
tissue  consists  of  contractile  cells — that  is  to  say,  of 
cells  with  the  sole  property  of  contraction.  When  the 
muscular  cell  contracts,  it  becomes  shorter  and  its  diam- 
eter increases.  This  brings  nearer  together  the  two 
parts  of  the  body  to  which  its  ends  are  attached.  In 
the  lower  metazoa  the  muscle-cells  have,  as  a  rule,  no 
particular  structure;  but  in  the  higher  animals  the  con- 
tractile plasm  undergoes  a  peculiar  differentiation,  which 
has  the  appearance  under  the  microscope  of  a  transverse 
streaking  of  the  long  cells.  On  this  ground  a  distinction 
is  drawn  between  striated  muscles  and  simple  non- 
striated  or  smooth  muscles.  The  more  vigorous,  rapid, 
and  definite  is  the  contraction  of  the  muscle,  the  more 
marked  is  the  streaky  character,  and  the  more  pro- 
nounced the  difference  between  the  doubly  refractive 
muscular  particles  from  the  simple  refractive.  The 
striated  muscle  is  "the  most  perfect  dynamo  we  know 
of"  (Verworn).  The  normal  heart  of  a  man  accomplish- 
es every  day,  according  to  Zuntz,  a  work  of  about  twenty 
thousand  kilogrammetres  —  in  other  words,  an  energy 
that  would  suffice  to  lift  to  a  height  of  one  metre  a 
weight  of  twenty  thousand  kilogrammes.  In  many  fly- 
ing insects  (gnats,  for  instance)  the  flying  muscles  make 
three  hundred  to  four  hundred  contractions  a  second. 

In  the  lower  and  higher  classes  of  the  metazoa  the 
muscle  amounts  to  no  more  than  a  thin  layer  of  flesh 
underneath  the  skin.  This  layer  consists  of  muscular 
cells,  which  come  originally  from  the  ectoderm  in  the 
form  of  internal  contractile  processes  of  the  skin-cells 
themselves,  as  in  the  polyps.  In  other  cases  the  muscle- 
cells  are  developed  from  the  connective-tissue  cells  of 
the  mesoderm,  the  middle  skin-layer,  as  in  the  cteno- 
phora.  This  mesenchymic  muscle  is  less  common  than 
epithelial  muscle.     In  most  of  the  askeletal  vermalia  the 

277 


THE    WONDERS    OF    LIFE 

subdermal  muscle  divides  into  two  layers — an  outer 
deposit  of  concentric  muscles  and  an  inner  layer  of 
longitudinal  muscles;  in  the  cylindrical  worms  (nema- 
todes, sagittae,  etc.)  the  latter  fall  into  four  longitudinal 
bands,  one  pair  of  upper  (dorsal)  and  a  pair  of  lower 
(ventral)  muscular  bands.  At  those  parts  of  the  body 
which  are  especially  used  for  locomotion  the  muscle  is 
more  strongly  developed,  as  in  the  belly-side  of  the 
crawling  worms  and  mollusks.  This  muscular  surface 
develops  into  a  kind  of  fleshy  "foot"  {podium)]  it 
assumes  a  great  variety  of  forms  in  the  various  classes 
of  mollusks.  In  most  of  the  snails  which  creep  on  the 
solid  ground  it  grows  into  a  muscular  "flat-foot" 
(gasteropoda) ;  in  the  mussels  which  cut  like  a  plough 
through  the  soft  slime  it  forms  a  sharp  "hatchet-foot" 
(pelecypoda) .  The  keel  -  snails  (heteropoda)  swim  by 
means  of  a  "keel-foot,"  which  works  like  the  screw 
of  a  ship ;  the  floating  -  snails  (pteropoda)  swim  un- 
steadily (like  butterflies  flying)  by  means  of  a  pair  of 
head-folds,  which  develop  from  the  side  of  the  anterior 
foot-section.  In  the  highest  mollusks,  the  cuttle-fishes 
(cephalopoda),  this  fore-foot  divides  into  four  or  five 
pairs  of  folds,  which  grow  into  long  and  very  muscular 
"head-arms";  the  numbers  of  strong  suckers  on  the 
latter  have  also  special  muscles.  In  all  these  non- 
articulate  mollusks  and  vermalia  hard  skeletons  are 
either  altogether  wanting  or  (like  the  external  shells  of 
the  mollusks)  they  have  no  functional  relation  to  the 
motor  muscles.  It  is  otherwise  in  the  higher  animals,  in 
which  we  find  this  relation  to  a  solid  jointed  skeleton 
that  becomes  a  passive  motor  apparatus. 

The  higher  groups  of  the  animal  kingdom  in  which  a 
characteristic  solid  skeleton  is  developed  and  forms  an 
important  starting-point  for  the  muscles,  as  well  as  a 
support  and  protection  for  the  whole  body,  are  the  three 
stems  of  the  echinoderms,  articulates,  and  vertebrates. 

278 


MOVEMENT 

All  three  groups  are  very  rich  in  forms,  and  far  surpass 
all  the  other  stems  of  the  animal  world  in  the  perfection 
of  their  locomotive  apparatus.  However,  the  disposition 
and  development  of  the  skeleton  as  a  passive  support, 
and  the  correlation  of  the  muscles  to  it  as  active  pulling- 
organs,  differ  very  much  in  the  three  classes,  and  are 
the  chief  factors  in  determining  their  characteristic 
types;  they  show  clearly  (even  apart  from  other  radical 
differences)  that  the  three  stems  have  arisen  indepen- 
dently of  each  other  from  three  different  roots  in  the 
vermalia  -  stem.  In  the  echinoderms  the  calcareous 
skeleton  is  formed  from  chalky  deposits  in  the  corium, 
in  the  articulates  from  chitine  secretions  of  the  epidermis, 
and  in  the  vertebrates  from  cartilage  of  an  internal 
chord-sheath  {cf.  Anthropogcny,  chapter  xxvi.). 

The  remarkable  stem  of  the  sea-dwelling  echinoderms 
or  "prickly  skins"  is  distinguished  from  all  the  other 
animal  groups  by  a  number  of  striking  pecu  iarities ; 
prominent  among  these  are  the  special  formation  of 
their  active  and  passive  motor  organs  and  the  curious 
form  of  their  individual  development.  In  this  onto- 
genesis two  totally  different  forms  appear  successively 
— the  simple  astrolarva  and  the  elaborately  organized 
and  sexually  mature  astrozoon.  The  small,  free-swim- 
ming astrolarva  has  the  general  structural  features  of 
the  rotatoria,  and  so  shows,  in  accordance  with  the 
biogenetic  law,  that  the  original  stem-form  of  the 
echinoderms  (the  amphoridea)  belonged  to  this  group 
of  the  vermalia.  I  have  briefly  explained  these  struct- 
ures in  the  History  of  Creation  (chapter  xxii.),  and  more 
fully  in  my  essay  on  the  amphoridea  and  cystoidea 
(1896).  The  little  astrolarva  has  no  muscles,  and  no 
water-vessels  or  blood-vessels.  It  moves  by  means  of 
vibratory  lashes  or  bands,  which  are  attached  to  special 
armlike  processes  at  the  surface.  These  arms  are 
regularly  developed  to  the  right  and  left  of  the  bilateral 

279 


THE    WONDERS    OF    LIFE 

symmetrical   larva   (which   as   yet   shows   no   trace   of 
the  five-rayed  structure).     By  a  very  curious  modifica- 
tion the  small  bilateral  astrolarva  is  transformed  into 
the   totally   different   pentaradial   astrozoon,   the   large 
sexually  mature   echinoderm  with   a   pronounced  five- 
rayed  structure.     (See  Art-forms  in  Nature,  plates  lo, 
20,  30,  40,  60,  70,  80,  90,  and  95.)     It  has  a  most  elab- 
orate organization,  with  muscles  and  cuticular  skeleton, 
blood-vessels  and  water-vessels,  etc.     A  section  of  the 
astrozoa — the   living   crinoidea,    or   sea-lilies,    and   the 
extinct  classes  of  blastoidea  (sea-buds),  cystoidea  (sea- 
apples),  and  amphoridea  (sea-urns) — grow  in  stationary 
fashion  at  the  bottom  of  the  sea.     The  other  four  extant 
classes  creep  about  in  the  sea — the  sea-gherkins  (holo- 
thuria),  the  star-fish  (asteridea  and  ophoidea),  and  the 
sea-urchins  (echinidea).  Their  creeping  motion  is  accom- 
plished by  two  kinds  of  organs — water-feet  and  skin- 
muscles.     The  latter  find  their  support  and  attachment 
in  solid  calcareous  needles,  which  develop  from  chalky 
deposits  in   the   corium.     As   these  calcareous  needles 
(which  are  particularly  conspicuous  in  the  sea-urchin) 
are  set  movably  in   special   protuberances  of  the  cal- 
careous plates  of  the  cuticular  skeleton,  and  moved  by 
little  muscular  needles,  the  echinoderms  walk  on  them 
as  if  they  were  stilts      Between  these,  however,  a  num- 
ber of  water-feet  arise  from  inside — thin  tubes  like  the 
fingers  of  a  glove,  which  are  filled  with  water  by  an  in- 
ternal conduit-system  (the  so-called  ambulacral  system) 
and  become  stiff.     These  very  extensible  ambulacral  feet, 
often  provided  with  a  suctorial  plate  at  the  closed  outer 
end,  serve  for  creeping,  sucking,  touching,  and  grasping. 
As  these  distinctive  motor  organs  of  the  echinoderms 
— both  the  ambulacral  feet  with  their  complicated  water- 
tubes  and  the  movable  needles  with   their  joints   and 
muscles — are  found  in  hundreds,  often  in  thousands,  on 
every  individual  five-rayed  astrozoon,  we  might  say  that 

280 


MOVEMENT 

the  echinoderms  have  the  most  advanced  and  com- 
pUcated  motor  organs  of  all  animals.  Their  historical 
development  is  perfectly  understood  from  its  earliest 
stages,  since  Richard  Semon  found,  in  his  ingenious 
pentactaea  theory  (1888),  the  correct  phylogenetic  mean- 
ing of  the  curious  embryology  of  the  echinoderms  dis- 
covered in  1845  by  Johannes  Miiller.  I  endeavored  in 
1896  to  establish  it  in  detail,  in  relation  to  paleontological 
discoveries,  in  the  essay  I  have  mentioned. 

The  large  stem  of  the  articulata  (the  richest  in  forms 
of  all  the  animal  stems)  comprises  three  chief  classes — 
the  annelids,  Crustacea,  and  tracheata.  All  three  groups 
agree  in  the  essential  features  of  their  organization, 
especially  in  the  external  articulation  or  metamerism  of 
the  long  bilateral  body,  and  also  in  the  repetition  of  the 
internal  organs  in  each  joint  or  segment.  In  each  joint 
there  is  originally  a  knot  of  the  ventral  nervous  system 
(the  ventral  marrow),  a  chamber  of  the  dorsal  heart, 
a  chitine-ring  of  the  cutaneous  skeleton,  and  a  corre- 
sponding group  of  muscles. 

Of  the  three  great  classes  of  the  articulates  the  annelids 
are  developed  directly  from  the  vermalia,  of  which  both 
the  nematoda  and  nemertinae  approach  very  closely  to 
them.  The  two  other  and  more  highly  organized  classes, 
the  Crustacea  and  tracheata,  are  younger  groups,  inde- 
pendently evolved  from  two  different  stems  of  the 
annelids.  The  annelids,  or  "ringed-worms"  (to  which, 
e.g.,  the  rain-worms  belong),  have  mostly  a  very  homo- 
geneous articulation ;  their  segments  or  metamera  repeat 
the  same  structure  to  a  great  extent,  especially  the 
subdermal  muscles.  In  a  transverse  section  we  see  in 
every  joint  underneath  the  layer  of  concentric  muscles 
a  pair  of  dorsal  and  a  pair  of  ventral  muscles.  Their 
epidermis  has  secreted  a  thin  covering  of  chitine,  in  the 
tubular  worms  a  leather-like  or  calcified  tube.  There 
are  no  bones  in   the   oldest  annelids;  in   the  younger 

281 


THE    WONDERS    OF    LIFE 

bristle-worms  (polychcFta)  one  or  two  pairs  of  short 
unjointed  feet  {parapodia)  are  found  in  every  joint. 

The  other  two  chief  classes  of  the  articulates  develop 
long  and  jointed  feet  of  very  varied  forms,  and  at  the 
same  time  assume  different  shapes  of  limbs  in  the  divi- 
sion of  labor.  This  heterogeneous  articulation  (heter- 
onomy)  is  the  more  pronounced  the  higher  the  whole 
organization.  This  is  equally  true  of  the  aquatic,  gill- 
breathing  Crustacea  (crabs,  etc.)  and  the  tracheata 
(terrestrial  animals  breathing  through  a  trachea,  the 
myriopods,  spiders,  and  insects).  In  the  higher  groups 
of  both  classes  the  number  of  limbs  is  usually  not  high- 
er than  fifteen  to  twenty ;  and  they  are  distributed  in 
three  principal  sections — head,  breast,  and  posterior  part 
of  the  body.  The  firm  covering  of  chitine,  which  was  deli- 
cate and  thin  in  most  of  the  annelids,  is  much  thicker  in 
most  of  the  crustacea  and  tracheata,  and  often  hardened 
by  a  calcareous  deposit ;  it  forms  a  solid  ring  of  chitine  in 
each  segment,  inside  which  the  motor  muscles  are  at- 
tached. The  successive  hard  rings  are  connected  by 
thin,  mobile,  intermediate  rings,  so  that  the  whole  body 
combines  firmness,  elasticity,  and  mobility  in  a  high 
degree.  The  structure  of  the  long  jointed  legs,  which 
are  fixed  in  pairs  on  each  segment,  is  very  similar. 
Hence  the  typical  character  of  the  motor  organs  of  the 
Crustacea  lies  in  the  circumstance  that  both  in  the  body 
and  the  limbs  the  muscles  are  attached  to  the  interior 
of  hollow  chitine  tubes,  and  go  in  these  from  member 
to  member. 

The  vertebrates  are  just  the  reverse  in  structure.  In 
their  case  a  solid  internal  skeleton  is  formed  in  the 
longitudinal  axis  of  the  body,  and  the  muscles  are  ex- 
ternal to  these  supporting  organs.  The  articulation  or 
metamerism  itself  is  not  visible  externally  in  the  verte- 
brates; it  is  only  seen  in  the  muscular  system  when  the 
non-articulated  skin  has  been  removed.     Then,  even  in 

382 


MOVEMENT 

the  lowest  skull-less  vertebrates,  the  acrania,  the  in- 
ternal skeleton  of  which  consists  merely  of  a  cylindrical, 
solid,  and  elastic  axial  rod  {chorda),  we  see  on  each  side 
a  row  of  muscular  plates  (fifty  to  eighty  in  the  amphi- 
oxus).  In  this  case  there  are  not  pairs  of  limbs,  and  it  is 
the  same  with  the  oldest  craniate  animals,  the  cvclostoma 
(myxinoida  and  petromyzonta).  It  is  only  with  the 
third  class  of  the  vertebrates,  the  true  fishes  {pisccs), 
that  two  pairs  of  lateral  limbs  appear — the  breast-fins 
and  belly-fins.  From  these,  in  their  terrestrial  descend- 
ants, the  oldest  amphibia  of  the  Carboniferous  Period, 
the  two  pairs  of  jointed  legs — fore-legs  (carpomela)  and 
hind-legs  (tarsomela) — are  derived.  These  four  lateral 
five-toed  legs  have  a  very  characteristic  and  compli- 
cated articulation,  both  in  the  internal  bony  skeleton 
and  the  muscular  system  that  encloses  this  and  is  at- 
tached to  it.  From  the  amphibia,  the  earliest  quadru- 
peds, this  locomotive  apparatus  is  transmitted  by  hered- 
ity to  their  descendants,  the  three  higher  classes  of  the 
vertebrates,  reptiles,  birds,  and  mammals.  As  I  have 
dealt  with  these  important  structures  fully  in  my  .4;/- 
thropogeny  (chapter  xxvi.),  and  given  a  number  of  illus- 
trations of  them,  I  must  refer  the  reader  to  that  work,' 
and  will  only  make  a  few  observations  on  the  mam- 
mals. 

Both  parts  of  the  motor  apparatus,  the  internal  bony 
skeleton  (the  passive  supporting  apparatus)  and  the 
external  muscular  system  (the  active  motor),  exhibit  a 
great  variety  of  construction  within  the  mammal  class, 
in  consequence  of  adaptation  to  the  most  different  habits 
and  functions.     We  have  only  to  compare  the  running 

*  A  translation  of  the  latest  edition  of  \y\e  Anthropogenic,  with 
the  full  number  of  frrsh  illustrations  (thirty  plates  and  five  hun- 
dred and  twelve  wood-cuts),  will  be  issued  very  shortly  by  the 
Rationalist  Press  Association,  under  the  title  of  The  Evolution 
of  Man. 

283 


THE    WONDERS    OF    LIFE 

carnivora  and  ungulata,  the  leaping  kangaroos  and 
jerboas,  the  burrowing  moles  and  hyperdaei,  the  flying 
cheiroptera  and  bats,  the  fishlike  swiraming  sirens  and 
whales,  and  climbing  lemures  and  apes.  In  all  these 
and  the  remaining  orders  of  the  mammals  the  whole 
regular  structure  of  the  motor  apparatus  is  strikingly 
adapted  to  the  habits  of  Hfe  which  have  been  formed  by 
this  adaptation  itself.  Nevertheless,  we  see  that  the 
essential  character  of  the  inner  organization  which  dis- 
tinguishes the  mammals  as  a  class  is  not  affected  by  this 
adaptation,  but  constantly  maintained  by  heredity. 
These  recognized  facts  of  comparative  anatomy  and 
ontogeny,  and  the  concordant  results  of  paleontology, 
prove  convincingly  that  all  living  and  fossil  mammals, 
from  the  lowest  ungulates  and  marsupials  to  the  ape 
and  man,  have  descended  from  one  common  stem-form, 
a  pro-mammal,  that  lived  in  the  Triassic  Period;  its 
earlier  ancestors  in  the  Permian  Period  were  reptiles, 
and,  in  the  Carboniferous  Period,  amphibia.  Among 
the  characters  of  the  locomotive  apparatus  which  are 
peculiar  to  mammals  we  have,  on  the  one  hand,  the 
structure  of  the  vertebral  column  and  the  skull,  and,  on 
the  other  hand,  the  formation  of  the  muscles  which  are 
attached  to  these  supporting  organs.  In  the  skull  we 
particularly  notice  the  formation  of  the  lower  jaw  and 
the  joint  by  which  it  is  connected  with  the  temporal 
bone.  This  joint  is  temporal,  and  so  distinguished  from 
the  square  joint  of  the  other  vertebrates.  The  latter  is 
found  in  the  mammals  in  the  tympanic  cavity  of  the 
middle-ear,  between  the  hammer  (the  modified  joint  of 
the  lower  jaw,  articulare)  and  the  anvil  (the  original 
quadraUmi).  In  harmony  with  this  remarkable  modifi- 
cation of  the  maxillary  joint,  the  corresponding  muscles 
have  naturally  also  undergone  a  considerable  trans- 
formation. A  distinctive  muscle  that  is  only  found  in 
the  mammals  and  regulates  their  respiration  is  the  dia- 

284 


MOVEMENT 

phragm,  which  completely  divides  the  abdominal  and 
thoracic  cavities;  the  various  muscles,  from  the  blending 
of  which  it  has  been  formed,  still  remain  separate  in  the 
other  vertebrates. 

The  many  organs  by  means  of  which  our  human  or- 
ganism accomplishes  its  manifold  movements  are  just 
the  same  as  in  the  apes,  and  the  mechanism  of  their 
action  is  in  no  way  different.  The  same  two  hundred 
bones,  in  the  same  order  and  composition,  form  our  in- 
ternal bony  skeleton;  the  same  three  hundred  muscles 
effect  our  movements.  The  differences  we  find  in  the 
form  and  size  of  the  various  muscles  and  bones  (and 
which  are,  as  is  well  known,  also  found  between  lower 
and  higher  races  of  men)  are  due  to  differences  in 
growth  in  consequence  of  divergent  adaptation.  On 
the  other  hand,  the  complete  agreement  in  the  con- 
struction of  the  whole  motor  apparatus  is  explained 
by  heredity  from  the  common  stem-form  of  the  apes 
and  men.  The  most  striking  difference  between  the 
movements  of  the  two  is  due  to  man's  adaptation  to 
the  erect  posture,  while  the  climbing  of  trees  is  the 
normal  habit  of  the  ape.  However,  it  is  unquestion- 
able that  the  former  is  an  evolution  from  the  latter. 
A  double  parallel  to  this  modification  is  seen  in  the 
jerboa  among  the  ungulates,  and  in  the  kangaroo 
among  the  marsupials.  Both  these,  in  springing,  use 
only  the  strong  hinder  extremities,  and  not  the  weaker 
fore-limbs;  as  a  result  of  this  their  posture  has  become 
more  or  less  erect.  Among  the  birds  we  have  an  analo- 
gous case  in  the  penguins  (aptoiodytcs)]  as  they  no 
longer  use  their  atrophied  wings  for  flight,  but  only  in 
swimming,  they  have  developed  an  erect  posture  when 
on  land. 

The  human  will  is  also  not  specifically  different  from 
that  of  the  ape  or  any  other  mammal;  and  its  micro- 
scopic organs,  the  neurona  in  the  brain  and  the  muscular 

2«5 


THE    WONDERS    OF    LIFE 

cells  in  the  flesh,  work  with  the  same  forms  of  energy, 
and  are  similarly  subject  to  the  law  of  substance.  Hence 
it  is  immaterial  for  the  moment  whether  one  believes  in 
the  freedom  of  the  will  according  to  the  antiquated 
creed  of  indeterminism,  or  whether  one  holds  it  to  be 
refuted  scientifically  by  the  arguments  of  modern  de- 
terminists;  in  either  case  the  acts  of  the  will  and  vol- 
untary movements  follow  the  same  laws  in  man  as  in 
the  ape.  The  high  development  of  the  function  in  civ- 
ilized man,  the  ample  differentiation  of  speech  and  mo- 
rality, art  and  science — in  a  word,  the  ethical  significance 
of  the  will  for  higher  culture — is  in  no  way  discordant 
to  this  monistic  and  zoologically  grounded  conception. 
In  the  lower  races  these  privileges  of  the  civilized  will 
are  only  found  in  a  slight  degree,  and  some  of  them  are 
wholly  wanting  among  the  lowest  races.  The  distance 
between  the  lowest  savage  and  the  most  civilized  human 
being  is  greater,  in  this  respect  also,  than  that  which 
separates  the  savage  from  the  anthropoid  ape.  How- 
ever, I  refer  the  reader  to  the  remarks  I  made  at  the 
close  of  the  seventh  chapter  of  the  Riddle  on  the  prob- 
lem of  the  freedom  of  the  will  and  the  infinite  literature 
relating  thereto.  The  reader  who  desires  to  go  further 
into  this  subject  will  find  it  well  treated  in  the  works 
of  Traugott  Trunk  (.1902)  and  Paul  Ree  (1903)  [also  in 
Dr.  Stout's  recent  little  manual  of  psychology  and  Mr. 
W.  H.  Mallock's  Religion  as  a  Credible  Doctrine']. 


XIII 
SENSATION 

Sensation  and  consciousness — Unconscious  and  conscious  sensa- 
tion —  Sensibility  and  irritability — Reflex  sensation  and 
perception  of  stimuli  —  Sensation  and  living  force — Re- 
action to  stimuli — Resolution  of  stimuli  —  External  and 
internal  stimuli — Conveyance  of  stimuli  —  Sensation  and 
striving — Sensation  and  feeling  —  Inorganic  and  organic 
sensation — Light  sensation,  phototaxis,  sight — Sensation 
of  warmth,  thermotaxis — Sensation  of  matter,  chemotaxis 
— Taste  and  smell — Erotic  chemicotropism— Organic  sen- 
sations—  Sensation  of  pressure — Geotaxis  —  Sensation  of 
sound — Electric  sensation. 

SENSATION  is  one  of  those  general  terms  that  have 
at  all  times  been  liable  to  the  most  varied  inter- 
pretations. Like  the  cognate  idea  of  the  "soul,"  it  is 
still  extremely  ambiguous.  During  the  eighteenth  cen- 
tury it  was  generally  believed  that  the  function  of 
sensation  was  peculiar  to  animals,  and  was  not  present 
in  plants.  This  opinion  found  its  most  important  ex- 
pression in  the  well-known  principle  in  Linnd's  System  a 
Natiircu:  "Stones  grow:  plants  grow  and  live:  animals 
grow,  live,  and  feel."  Albrecht  Haller,  who  gathered 
up  all  the  knowledge  of  his  time  relating  to  organic  life 
in  his  Elemcnta  Physiologic^  (1766),  distinguished  as  its 
two  chief  characters  "sensibility"  and  "irritability." 
The  one  he  ascribed  exclusively  to  the  nerves,  and  the 
other  to  the  muscles.  This  erroneous  idea  was  sub- 
sequently refuted,  and  in  our  own  time  irritability  is 
conceived  to  be  a  general  property  of  all  living  matter. 

287 


THE    WONDERS    OF    LIFE 

The  great  advance  made  by  the  comparative  anatomy 
and  experimental  physiology  of  animals  and  plants  in 
the  first  half  of  the  nineteenth  century  brought  to  light 
the  fact  that  irritability  or  sensibility  is  a  common 
quality  of  all  organisms,  and  that  it  is  one  of  the  princi- 
pal characteristics  of  vital  force  {cf.  chapter  ii.).  The 
greatest  merit  in  connection  with  its  experimental  study 
attaches  to  the  famous  Johannes  Miiller.  In  his  classi- 
cal Manual  of  Human  Physiology  (1840)  he  established 
his  theory  of  the  specific  energy  of  the  nerves  and  their 
dependence  on  the  sense-organs  on  the  one  hand  and 
the  mental  life  on  the  other.  He  devoted  the  fifth  chap- 
ter of  his  book  to  the  former  and  the  sixth  to  the  latter, 
approaching  particularly  to  Spinoza  in  his  general  psy- 
chological views;  he  treated  psychology  as  a  part  of 
physiology,  and  thus  put  on  a  sound  scientific  basis  that 
naturalistic  conception  of  the  place  of  psychology  in  the 
biological  system  which  we  now  regard  as  the  correct 
view.  At  the  same  time  he  proved  that  sensation  is 
a  function  of  the  organism  as  much  as  movement  or 
nutrition. 

The  view  of  sensation  that  prevailed  in  the  second  half 
of  the  nineteenth  century  was  very  different.  On  the 
one  hand  the  experimental  and  comparative  physiology 
of  the  sense-organs  and  the  nervous  system  immensely 
enriched  our  exact  knowledge  by  the  invention  of  in- 
genious methods  of  research  and  the  use  of  the  great 
advance  made  by  physics  and  chemistry.  The  famous 
investigations  of  Helmholtz  and  Hertwig  on  the  physics 
of  the  senses,  of  Matteucci  and  Dubois-Revmond  on  the 
electricity  of  the  muscles  and  nerves,  and  the  great 
progress  made  in  vegetal  physiology  by  Sachs  and 
Pfeffer,  and  in  physiological  chemistry  by  Moleschott 
and  Bunge,  enabled  us  to  realize  that  even  the  most 
mysterious  of  the  wonders  of  life  depend  on  physical 
and  chemical  processes.     By  the  application  of  the  dif- 

288 


SENSATION 

ferent  stimuli — light,  heat,  electricity,  and  chemical 
action — to  the  various  sensitive  or  irritable  organs  un- 
der definitely  controlled  conditions,  scientists  succeeded 
in  subjecting  with  exactness  a  great  part  of  the  phe- 
nomena of  stimulation  to  mathematical  measurements 
and  formulae.  The  science  of  the  stimuli  and  their 
effects  acquired  a  strictly  physical  character. 

On  the  other  hand,  in  most  striking  contradiction  to 
the  immense  advance  of  experimental  physiology,  we 
see  that  the  general  conception  of  the  various  vital  proc- 
esses, and  especially  of  the  inner  nerve-action  that  con- 
verts the  functions  of  the  senses  into  mental  life,  is  most 
curiously  neglected.  Even  the  fundamental  idea  of 
sensation,  which  plays  the  chief  part  in  it,  is  disregarded 
more  and  more.  In  many  of  the  most  valuable  modern 
manuals  of  physiology,  containing  long  chapters  on 
stimuli  and  stimulation,  there  is  little  or  no  mention  of 
sensation  as  such.  This  is  chiefly  due  to  the  mischiev- 
ous and  unjustifiable  gulf  that  has  once  more  been  arti- 
ficially created  between  physiology  and  psychology.  As 
the  "exact"  physiologists  found  the  study  of  the  inner 
psychic  processes  which  take  p  ace  in  sense-action  and 
sensation  inconvenient  and  unprofitable,  they  gladly 
handed  over  this  difficult  and  obscure  field  to  the  "psy- 
chologists proper" — in  other  words,  to  the  metaphysi- 
cians, who  had  for  the  starting  -  point  of  their  airy 
speculations  the  belief  in  an  immortal  soul  and  divine 
consciousness.  The  psychologists  readily  abandoned  the 
inconvenient  V)urden  of  experience  and  a  posteriori 
knowledge,  to  which  the  modern  anatomic  physiology 
of  the  brain  laid  special  claim. 

The  greatest  and  most  fatal  error  committed  by 
modern  physiology  in  this  was  the  admission  of  the 
baseless  dogma  that  all  sensation  must  be  accompanied 
by  consciousness.  As  most  physiologists  share  the  view 
of  Dubois-Reymond,  that  consciousness  is  not  a  natural 
19  289 


THE    WONDERS    OF    LIFE 

phenomenon,  but  a  hyperphysical  problem,  they  leave 
it  and  this  inconvenient  "sensation"  outside  the  range 
of  their  researches.  This  decision  is,  naturally,  very 
agreeable  to  the  prevalent  metaphysics;  it  has  just  as 
much  interest  in  the  transcendental  character  of  sensa- 
tion as  in  the  liberty  of  the  will,  and  thus  the  whole  of 
psychology  passes  from  the  empirical  province  of  nat- 
ural science  into  the  mystical  province  of  mental  science. 
For  its  foundation  they  then  take  the  "critical  theory 
of  knowledge,"  which  ignores  the  results  of  the  real 
physiological  organs — the  senses,  nerves,  and  brain — 
and  draws  its  "superior  wisdom"  from  the  inner  mirror- 
ing of  self  by  the  introspective  analysis  of  presentations 
and  their  associations.  It  is  extraordinary  that  even 
distinguished  monistic  physiologists  suffer  themselves 
to  be  taken  in  with  this  sort  of  metaphysical  jugglery, 
and  dismiss  the  whole  of  psychology  from  their  prov- 
ince ;  their  psychomonism  readmits  the  soul  as  a  super- 
natural entity,  and  delivers  it,  in  contrast  with  the 
"world  of  bodies,"  from  the  yoke  of  the  law  of  sub- 
stance. 

Impartial  reflection  on  our  personal  experience  during 
sensation  and  consciousness  will  soon  convince  us  that 
these  are  two  different  physiological  functions,  which  are 
by  no  means  necessarily  associated ;  and  the  same  may 
be  said  of  the  third  principal  function  of  the  soul — the 
will.  When  we  learn  an  art — for  instance,  painting  or 
playing  the  piano — we  need  months  of  daily  practice  in 
order  to  become  expert  at  it.  In  this  we  experience 
every  day  hundreds  of  thousands  of  sensations  and 
movements  which  are  learned  and  repeated  with  full 
consciousness.  The  longer  we  continue  the  practice 
and  the  more  we  adapt  and  accustom  ourselves  to  the 
function,  the  easier  and  less  conscious  it  becomes.  And 
when  we  have  practised  the  art  for  some  years,  we  paint 
our  picture  or  play  our  piano  unconsciously;  we  think 

290 


SENSATION 

no  longer  of  all  the  small,  subtle  shades  of  sensation  and 
acts  of  will  which  were  necessary  in  learning.  The  mere 
impulse  of  the  will  to  paint  the  picture  once  more  or 
play  the  piece  again  suffices  to  release  the  whole  chain 
of  complicated  movements  and  accompanying  sensations 
which  had  originally  to  be  learned  slowly,  laboriously, 
and  with  full  consciousness.  An  experienced  pianist 
plays  the  most  difficult  piece — if  he  has  learned  it  and 
repeated  it  thousands  of  times — "half  in  a  dream." 
But  it  needs  only  a  slight  accident,  such  as  a  mistake  or 
a  sudden  interruption,  to  bring  back  the  wandering 
attention  to  the  work.  The  piece  is  now  played  with 
clear  consciousness.  The  same  may  be  said  of  thousands 
of  sensations  and  movements  which  we  learned  at  first 
consciously  in  childhood,  and  then  repeat  daily  after- 
wards without  noticing — such  as  in  walking,  eating, 
speaking,  and  so  on.  These  familiar  facts  prove  of  them- 
selves that  consciousness  is  a  complicated  function  of  the 
brain,  by  no  means  necessarily  connected  with  sensation 
or  will.  To  bind  up  the  ideas  of  consciousness  and  sensa- 
tion inseparably  is  the  more  absurd,  as  the  mechanism  or 
the  real  nature  of  consciousness  seems  very  obscure  to 
us,  while  the  idea  of  it  is  perfectly  clear:  we  know  that 
we  know,  feel,  and  will. 

The  word  "irritability"  is  generally  taken  by  modem 
physiology  to  mean  that  the  living  matter  has  the 
property  of  reacting  on  stimuli  —  that  is  to  say,  of 
responding  by  changes  in  itself  to  changes  in  its  en- 
vironment. The  stimulus,  or  action  of  a  foreign  energy, 
must,  however,  be  felt  by  the  plasm  before  the  cor- 
responding stimulated  movement  (in  the  form  of  va- 
rious manifestations  of  energy)  will  be  produced.  Hence 
the  question  whether  this  sensation  is  (in  certain 
cases)  associated  with  consciousness  or  (generally) 
remains  unconscious  is  of  a  subordinate  interest.  The 
plant  that  is  caused  to  open  its  floral   calyx  by   the 

291 


THE    WONDERS    OP    LIFE 

stimulus  of  light  acts  just  as  unconsciously  in  this  as  the 
coral  that  spreads  out  its  crown  of  tentacles  under  the 
same  influence;  and  when  the  sensitive  carnivorous 
plant  {dioncea  or  drosera)  closes  its  leaves  in  order  to 
catch  and  destroy  the  insect  sitting  on  them,  it  acts  in 
the  same  way  as  the  sensitive  actinia  or  coral  when  it 
draws  in  its  crown  of  tentacles  for  the  same  object — in 
both  cases  without  consciousness!  We  call  these  uncon- 
scious movements  "reflex  actions."  I  have  dealt  some- 
what fully  with  these  reflex  movements  in  the  seventh 
chapter  of  the  Riddle,  and  must  refer  the  reader  thereto. 
This  elementary  psychic  function  always  depends  on  a 
conjunction  of  sensation  and  movement  (in  the  widest 
sense).  The  movement  that  the  stimulus  provokes  is 
always  preceded  by  a  sensation  of  the  influence  exerted. 

Modern  physiology  makes  desperate  efforts  to  avoid 
the~use  of  the  word  "sensation"  and  substitute  for  it 
"perception  of  "stimulus."  The  chief  blame  for  this 
misleading  expressioii^is  due  to  the  arbitrary  and  un- 
justified separation  of  psychology  from  physiology.  The 
latter  is  supposed  to  occupy  itself  with  the  material 
phenomena  and  physical  changes,  leaving  to  psychology 
the  privilege  of  dealing  with  the  higher  mental  phe- 
nomena and  metaphysical  problems.  As  we  reject  this 
distinction  altogether  on  monistic  principles,  we  cannot 
consent  to  separate  sensation  from  the  perception  of 
stimuli — whether  this  sensation  be  accompanied  with 
consciousness  or  not.  Moreover,  modern  physiology,  in 
spite  of  its  desire  to  keep  clear  of  psychology,  sees  itself 
compelled  in  a  thousand  ways  to  use  the  words  "sensa- 
tion" and  "sensitive,"  especially  in  the  science  of  the 
organs  of  sense. 

What  we  call  sensation  or  perception  of  stimuli  may 
be  regarded  as  a  special  form  of  the  living  force  or 
actual  energy  (Ostwald).  Sensitiveness  or  irritability, 
on  the  other  hand,  is  a  form  of  virtual  or  potential 

292 


SENSATION 

energy.  The  living  substance  at  rest,  which  is  sensitive 
or  irritable,  is  in  a  state  of  equilibrium  and  indifTerence 
to  its  environment.  But  the  active  plasm,  that  receives 
and  feels  a  stimulus,  has  its  equilibrium  disturbed,  and 
corresponds  to  the  change  in  its  environment  and  its 
internal  condition.  This  response  of  the  organism  to  a 
stimulus  is  called  "reaction" — a  term  that  is  also  used 
(in  the  same  sense)  in  chemistry  to  express  the  inter- 
action of  bodies  on  each  other.  At  each  stimulation  the 
virtual  energy  of  the  plasm  (sensitiveness)  is  converted 
into  living  or  kinetic  force  (sensation).  The  share  of  the 
stimulus  in  this  conversion  is  described  as  a  "release" 
of  energy. 

The  term  "reaction"  stands  in  general  for  the  change 
which  any  body  experiences  from  the  action  of  an- 
other body.  Thus,  for  instance,  to  take  the  simplest 
case,  the  interaction  of  two  substances  in  chemistry  is 
called  a  reaction.  In  chemical  analysis  the  word  is  used 
in  a  narrower  sense  to  denote  that  action  of  one  body 
on  another  which  serves  to  reveal  its  nature.  Even 
here  we  must  assume  that  the  two  bodies  feel  their 
different  characters ;  otherwise  they  could  not  act  on  each 
other.  Hence  every  chemist  speaks  of  a  more  or  less 
"sensitive  reaction."  But  this  process  is  not  different 
in  principle  from  the  reaction  of  the  living  organism  to 
outer  stimuli,  whatever  be  their  chemical  or  physical 
nature.  And  there  is  no  more  essential  difference  in 
psychological  reaction,  which  is  always  bound  up  with 
corresponding  changes  in  the  psychoplasm,  and  so  with 
a  chemical  conversion  of  energy.  In  this  case,  however, 
the  process  of  reaction  is  much  more  complicated,  and 
we  can  distinguish  several  parts  or  phases  of  it:  i,  the 
outer  excitation;  2,  the  reaction  of  the  sense-organ; 
3,  the  conducting  of  the  modified  impression  to  the 
central  organ;  4,  the  internal  sensation  of  the  conducted 
impression;  and,  5,  consciousness  of  the  impression. 

293 


THE    WONDERS    OF    LIFE 

The  important  idea  of  a  release  of  energy — the  term 
we  give  to  the  effect  of  the  stimulus — is  also  used  in 
physics.  If  we  put  a  piece  of  burning  wood  in  a  barrel 
of  powder,  the  flame  causes  an  explosion.  In  the  case  of 
dynamite  a  simple  mechanical  shock  is  enough  to  pro- 
duce the  most  enormous  expenditure  of  force  in  the  ex- 
plosive matter.  When  we  discharge  a  bow  the  slight 
pressure  of  the  finger  on  the  tense  cord  suffices  to  send  out 
the  arrow  or  bolt  on  its  deadly  mission.  So  also  a  sound 
or  a  ray  of  light  that  strikes  the  ear  or  eye  suffices  to 
bring  about  a  number  of  complex  effects  by  means  of  the 
nervous  system.  In  the  fertilization  of  the  ovum  by  the 
male  sperm  the  chemical  conjunction  of  the  two  forma- 
tive principles  is  sufficient  to  cause  the  growth  of  a  new 
human  being  out  of  the  microscopic  plasma-globule,  the 
stem-cell  (cytula).  In  these  and  thousands  of  other 
reactions  a  very  slight  shock  suffices  to  provoke  the 
largest  effects  in  the  stimulated  substance.  This  shock, 
which  we  call  a  release  of  energy,  is  not  the  direct  cause 
of  the  considerable  result,  but  merely  the  occasion  for 
bringing  it  about.  In  these  cases  we  have  always  a 
vast  accumulation  of  virtual  energy  converted  into  living 
force  or  work.  The  magnitude  of  the  two  forces  has  no 
relation  at  all  to  the  smallness  of  the  shock  which  led  to 
the  conversion.  In  this  we  have  the  difference  between 
stimulated  action  and  the  simple  mechanical  action  of 
two  bodies  on  each  other,  in  which  the  quantity  of  the 
energy  expended  is  equal  on  both  sides,  and  there  is  no 
stimulus. 

The  immediate  effect  of  a  stimulus  on  living  matter 
can  best  be  followed  in  external  physical  or  chemical 
stimuli,  such  as  light,  heat,  pressure,  sound,  electricity, 
and  chemical  action.  In  these  cases  physical  science  is 
often  able  to  reduce  the  life-process  to  the  laws  of 
inorganic  nature.  This  is  more  difficult  with  the  internal 
stimuli  within  the  organism  itself,  which  are  only  partly 

294 


SENSATION 

exposed  to  physiological  investigation.  It  is  true  that 
here  also  the  task  of  science  is  to  reduce  all  the  bio- 
logical phenomena  to  physical  and  chemical  laws.  But 
it  can  only  discharge  a  part  of  this  difficult  task,  as 
the  phenomena  are  too  complicated,  and  their  conditions 
too  little  known  in  detail,  to  say  nothing  of  the  crudeness 
and  imperfectness  of  our  methods  of  research.  Yet,  in 
spite  of  all  this,  comparative  and  phylogenetic  physiology 
convinces  us  that  even  the  most  complicated  of  our 
internal  excitations,  and  particularly  the  mental  activity 
of  the  brain,  depend  just  as  much  as  the  outer  stimula- 
tions on  physical  processes,  and  are  equally  subject  to 
the  law  of  substance.  This  is,  in  fact,  true  of  reason 
and  consciousness. 

In  man  and  all  the  higher  animals  the  stimuli  are 
received  by  the  organs  of  sense  and  conducted  by  their 
nerves  to  the  central  organ.  In  the  brain  they  are  either 
converted  into  specific  sensations  in  the  sense-centres, 
or  conveyed  to  the  motor  region,  where  they  provoke 
movements.  The  conduction  of  stimuli  is  simpler  in 
the  lower  animals  and  the  plants;  the  tissue-cells  either 
directly  affect  each  other  or  are  connected  by  fine  threads 
of  plasm.  In  the  unicellular  protists  the  stimulus  which 
strikes  one  particular  spot  of  the  surface  may  be  imme- 
diately communicated  to  the  other  parts  of  the  unified 
plasmic  body. 

We  shall  see  in  the  course  of  our  inquiry  that  the 
simplest  form  of  sensation  (in  the  widest  sense)  is 
common  to  inorganic  and  organic  bodies,  and  thus  that 
sensitiveness  is  really  a  fundamental  property  of  all 
matter,  or,  more  correctly,  all  substance.  We  may, 
therefore,  ascribe  sensation  to  the  constituent  atoms  of 
matter.  This  fundamental  thought  of  hvlozoism,  ex- 
pressed long  ago  by  Empedocles,  has  lately  been  very 
definitely  urged,  especially  by  Fechner.  However,  the 
able  founder  of  psycho-physics  {cf.  the  Riddle,  p.  35) 

295 


THE    WONDERS    OF    LIFE 

assumes  that  consciousness  (or  thought,  in  the  Spinozis- 
tic  sense)  always  accompanies  this  universal  property  of 
sensation.  In  my  opinion,  consciousness  is  a  secondary 
psychic  function,  only  found  in  man  and  the  higher 
animals,  and  bound  up  with  the  centralization  of  the 
nervous  system.  Hence  it  is  better  to  speak  of  the  un- 
conscious sensation  of  the  atoms  as  feeling  (cDstJtesis) , 
and  their  unconscious  will  as  inclination  {tropesis).  It 
finds  expression  in  the  one-sided  action  of  a  stimulus  as 
a  "directed  movement"  or  "stimulated  movement" 
{tropismus  or  taxis). 

The  familiar  ideas  of  sensation  and  feeling  are  often 
confused,  and  employed  in  very  different  ways  in  both 
physiology  and  psychology.  The  metaphysical  tendency 
which  so  completely  separates  the  two  sciences,  and  the 
physiological  tendency  which  agrees  with  it,  regard 
feeling  as  a  purely  psychic  or  spiritual  function,  whereas 
in  the  case  of  sensation  they  have  to  admit  the  connec- 
tion with  bodily  functions,  especially  sense-action.  In  my 
opinion,  the  two  ideas  are  purely  physiological  and  can- 
not be  sharply  separated,  or  only  in  the  sense  that 
sensation  relates  more  to  the  external  (objective)  part  of 
the  sensory  nerve-process,  and  feeling  to  the  internal 
(subjective)  part.  Hence  we  may  define  the  difference 
in  a  general  way  by  saying  that  sensation  perceives  the 
different  qualities  of  the  stimuli,  and  feeling  only  the 
quantity,  the  positive  or  negative  action  of  the  stimulus 
(pleasure  or  pain).  In  this  last  and  widest  sense  we 
may  ascribe  the  feeling  of  pleasure  and  pain  (in  the 
contact  with  qualitatively  differing  atoms)  to  all  atoms, 
and  so  explain  the  elective  affinity  in  chemistry  (syn- 
thesis of  loving  atoms,  inclination;  analysis  of  hating 
atoms,  disinclination). 

Our  monistic  system  (whether  it  be  taken  as  energism 
or  materialism,  or  more  correctly  as  hylozoism)  regards 
all  substance  as  having  "soul" — that  is  to  say,  endowed 

296 


SENSATION 

with  energy.  In  the  chemical  analysis  of  organisms  we 
do  not  find  any  elements  that  are  not  found  in  inorganic 
nature;  we  find  that  the  movements  in  organisms  obey 
the  same  laws  of  mechanics  as  the  latter ;  we  believe  that 
the  conversion  of  energ}.-  in  the  living  matter  occurs  in 
the  same  way,  and  is  provoked  by  the  same  stimuli,  as 
in  inorganic  matter.  We  are  forced  to  conclude  from 
these  experiences  that  the  perception  of  stimuli — sensa- 
tion in  the  objective  and  feeling  in  the  subjective  sense — 
is  also  generally  present  in  the  two.  All  bodies  are  in  a 
certain  sense  "sensitive."  It  is  just  in  this  dynamic 
conception  of  substance  that  monism  differs  essentially 
from  the  materialistic  system,  which  regards  one  part 
of  matter  as  "dead"  and  insensitive.  In  this  we  have 
the  best  means  of  joining  consistent  materialism  or 
realism  with  consistent  spiritualism  or  idealism.  But, 
as  a  first  condition  of  such  a  union,  we  must  demand 
a  recognition  that  organic  life  is  subject  to  the  same 
general  laws  as  inorganic  nature.  In  both  cases  the 
outer  world  acts  alike  as  a  stimulus  on  the  inner  world 
of  the  body.  We  can  easily  see  this  if  we  glance  at  the 
various  kinds  of  sensation  which  correspond  to  the 
various  kinds  of  stimuli.  Light  and  heat,  external  and 
internal  chemical  stimuli,  pressure  and  electricity,  cause 
analogous  sensations  and  modifications  in  their  effect  on 
organic  and  inorganic  bodies. 

The  effect  which  the  light  -  stimulus  has  on  living 
matter,  the  sensation  of  light  that  results,  and  the 
chemical  changes  of  energy  that  follow,  are  of  great 
physiological  importance  in  all  organisms.  We  might 
even  say  that  sunlight  is  the  first,  oldest,  and  chief 
source  of  organic  life;  all  other  exertions  of  force  depend 
in  the  long  run  on  the  radiant  energy  of  sunlight.  The 
oldest  and  most  important  function  of  plasm — one  which 
is  at  the  same  time  a  cause  of  its  formation — is  carbon- 
assimilation ;   and   this   plasmodomism   is   directly   de- 

297 


THE    WONDERS    OF    LIFE 

pendent  on  sunlight.  If  it  acts  in  a  one-sided  way,  it 
causes  the  particular  form  of  stimulation  which  we 
call  phototaxis  or  heliotropism.  This  is  of  a  positive 
character — that  is  to  say,  they  turn  towards  the  source 
of  the  light — in  the  great  majority  of  organisms,  both 
protists  and  histona.  Everybody  knows  that  flowers 
that  are  growing  in  the  window  of  a  room  turn  to  the 
light.  However,  many  organisms  which  have  grown 
accustomed  to  living  in  the  dark  are  heliotropically  nega- 
tive; they  shun  the  light  and  seek  darkness,  such  as  the 
fungi,  many  lucifugous  mosses  and  ferns,  and  many 
deep-sea  animals. 

The  principal  organs  of  light-sensation  in  the  higher 
animals  are  the  eyes;  they  are  wanting  in  many  of  the 
lower  animals  as  well  as  the  plants.  The  essential 
difference  between  the  real  eye  and  a  part  of  the  skin 
that  is  merely  sensitive  to  light  is  that  the  eye  can  form 
a  picture  of  objects  in  the  outer  world.  This  faculty  of 
vision  begins  with  the  formation  of  a  small  convergent 
lens,  a  bi-convex  refracting  body  at  a  certain  spot  on  the 
surface.  Dark  pigment-cells  which  surround  it  absorb 
the  light-rays.  From  this  first  phylogenetic  form  of  the 
organ  of  vision  up  to  the  elaborate  human  eye  there  is  a 
long  scale  of  evolutionary  stages — not  less  extensive  and 
remarkable  than  the  historical  succession  of  artificial 
optical  instruments  from  the  simple  lens  to  the  com- 
plicated modem  telescope  or  microscope.  This  great 
"wonder  of  life" — the  long  scale  of  the  evolution  of  the 
eye — has  an  interesting  bearing  on  many  important 
questions  of  general  physiology  and  phylogeny.  We  can, 
in  this  case,  see  clearly  how  a  very  complicated  and 
purposive  apparatus  can  arise  in  a  purely  mechanical 
way,  without  any  preconceived  design  or  plan.  In  other 
words,  we  can  see  how  an  entirely  new  function — and 
one  of  its  principal  functions,  vision — has  arisen  in  the 
organism  by  mechanical  means. 

298 


SENSATION 

The  advanced  vision  of  the  higher  animals  is  made  up 
of  a  great  number  of  different  functions,  with  a  corre- 
sponding complexity  of  detail  in  the  anatomic  structure 
of  the  eye.  No  other  organ,  after  the  brain,  is  so  neces- 
sary as  the  eye  for  the  multifarious  vital  activities  of 
the  higher  animals,  and  especially  for  the  mental  life  of 
civilized  man  and  the  progress  of  art  and  science.  What 
would  the  human  mind  be  if  we  could  not  read,  write, 
and  draw,  and  have  a  direct  knowledge  through  the  eye 
of  the  forms  and  colors  of  the  outer  world  ?  Yet  this  in- 
valuable structure  is  only  the  highest  and  most  perfect 
stage  in  the  long  chain  of  evolutionary  processes  which 
has  its  starting-point  in  the  general  sensitiveness  to  light, 
or  the  photic  irritability  of  plasm.  However,  we  find  a 
number  of  varieties  and  grades  of  this  even  among  the 
unicellular  protists,  and,  indeed,  the  very  lowest  and 
oldest  of  the  protists,  the  monera.  Various  species  of 
both  the  chromacea  and  the  bacteria  are  heliotropic  to 
different  degrees,  and  have  a  fine  sensitiveness  to  the 
strength  of  the  light  stimulus. 

The  stimulating  effect  which  light  has  on  the  homo- 
geneous plasm  of  the  monera  is  also  found  in  a  number 
of  inorganic  bodies.  In  these  cases  the  photic  stimulus 
produces  partly  chemical  and  partly  mechanical  changes. 
Every  chemist  speaks  of  substances  that  are  more  or  less 
"sensitive"  to  light;  the  photographer  speaks  of  his 
"sensitive  plates,"  the  painter  of  his  "sensitive  colors." 
Many  chemical  compounds  are  so  sensitive  to  light  that 
they  are  destroyed  at  once  in  sunlight,  and  so  have  to 
be  kept  in  the  dark.  There  is  no  other  word  but  "sen- 
sation" to  express  the  attitude  of  the  atoms  towards 
each  other  which  becomes  so  conspicuous  in  these  cases 
under  the  influence  of  sunlight.  It  seems  to  me  that  this 
phenomenon  is  a  clear  justification  of  our  hylozoic  monism 
when  it  affirms  that  all  matter  is  psychic.  In  metaphys- 
ics sensation  is  held  to  be  an  essential  property  of  the  soul. 

299 


THE    WONDERS    OF    LIFE 

In  the  same  general  way  as  light  the  heat-stimulus 
acts  on  organisms,  and  causes  the  sensations,  sometimes 
pleasant  and  sometimes  unpleasant,  which  we  call  the 
subjective  feeling  of  heat,  warmth,  coolness,  or  cold. 
The  sense-organ  that  receives  these  impressions  of 
temperature  is  the  surface  of  the  unicellular  plasmic 
body  in  the  protists,  and  the  skin  (epidermis)  that 
protects  the  surface  from  the  outer  world  in  the  histona. 
In  all  living  things  the  temperature  of  the  surrounding 
medium  (water  or  air)  has  a  great  influence  in  regulating 
the  life-processes;  in  the  stationary  animals  and  plants 
it  is  the  temperature  of  the  ground  to  which  they  are 
attached.  This  temperature  must  always  be  between 
the  freezing-point  and  boiling-point  of  water,  as  fluid 
water  is  indispensable  for  the  imbibition  of  the  living 
matter  and  the  molecular  movements  within  the  plasm. 
At  the  same  time,  some  of  the  lower  protists  (chromacea, 
bacteria)  can  endure  very  high  and  very  low  temperatures, 
but  only  for  a  short  time.  Some  protists  (monera  and 
diatomes)  can  stand  a  temperature  of  200°  C.  for  several 
days,  and  others  can  be  heated  above  boiling-point 
without  being  killed.  Arctic  and  High-Alpine  plants 
and  animals  may  be  in  a  frozen  condition  for  several 
months,  yet  live  again  when  they  are  thawed.  How- 
ever, the  resistance  to  these  extremes  of  cold  lasts  for 
only  a  limited  time,  and  in  the  frozen  state  all  vital 
functions  are  at  a  standstill. 

In  the  great  majority  of  living  things  the  vital  activity 
is  confined  within  narrow  limits  of  temperature.  Many 
plants  and  animals  in  the  tropics  which  have  been 
accustomed  for  thousands  of  years  to  the  constancy  of  the 
hot  equatorial  climate  can  endure  only  very  restricted 
variations  of  temperature.  On  the  other  hand,  many  of 
the  inhabitants  of  Central  Siberia,  where  the  climate  is 
very  hot  in  the  short  summer  and  very  cold  in  the  long 
winter,   can   stand   great  variations,     Thus   the   living 

300 


SENSATION 

plasm  has  experienced  considerable  changes  in  its  sense 
of  warmth  through  adaptation  to  different  environments; 
not  only  the  maximum  and  the  minimum,  but  the  opti- 
mum (most  agreeable  point),  is  subject  to  very  great 
variations.  This  can  easily  be  observed  and  followed 
experimentally  in  the  phenomena  of  thermotaxis  or 
thermotropism — that  is  to  say,  the  effect  that  follows 
from  a  one  -  sided  action  of  the  heat  -  stimulus.  The 
organism  that  falls  below  the  minimum  of  temperature 
is  said  to  be  stiff  with  cold,  while  the  organism  that  rises 
above  the  maximum  is  stiff  with  heat. 

The  heat-stimulus  acts  on  inorganic  as  well  as  organic 
bodies,  like  the  light-stimulus.  The  law  holds  good  in 
both  cases  that  higher  temperatures  increase  sensation, 
while  lower  ones  paralyze  it.  There  is  a  minimum,  an 
optimum,  and  a  maximum,  for  many  chemical  and 
physical  processes  in  the  inorganic  world.  As  far  as 
the  melting  effect  of  water  is  concerned,  freezing  is  the 
minimum  of  the  heat  stimulus  and  boiling  the  maximum. 
As  the  various  chemical  compounds  meet  in  water  at  very 
different  temperatures,  we  have  an  optimum  for  many 
substances — that  is  to  say,  a  degree  of  warmth  which  is 
most  favorable  to  the  solution  of  a  given  quantity  of  a 
solid  body  in  water.  On  the  whole,  the  law  holds  for 
chemical  processes  that  they  are  accelerated  by  high 
temperatures  and  retarded  by  low  ones  (like  the  human 
passions!);  the  former  have  a  stimulating  and  the  lat- 
ter a  benumbing  effect.  As  the  action  of  the  various 
chemical  compounds  on  each  other  is  determined  by 
the  nature  of  the  elements  and  their  affinities,  we  must 
trace  the  variations  in  their  conduct  towards  thermic 
stimuli  to  a  sensation  of  temperature  in  the  constituent 
atoms;  increase  of  temperature  stimulates  it,  while  de- 
crease lessens  or  paralyzes  it.  Here,  again,  the  simple 
inorganic  processes  have  a  general  resemblance  to  the 
complicated  vital  phenomena  in  the  organic  body. 

301 


THE    WONDERS    OF    LIFE 

Since  we  regard  the  whole  of  organic  life  as,  in  the 
ultimate  analysis,  merely  a  very  elaborate  chemical 
process,  we  shall  quite  expect  that  chemical  stimuli  are 
the  most  important  factors  in  sensation.  And  this  is  so 
in  point  of  fact;  from  the  simplest  moneron  up  to  the 
most  highly  differentiated  cell  and  on  to  the  flower  in 
the  plant  and  the  mental  life  of  man,  the  vital  processes 
are  dominated  by  chemical  forces  and  conversions  of 
energy,  which  are  set  in  play  by  external  or  internal 
chemical  stimuli.  The  excitation  which  they  produce 
is  called,  in  a  general  way,  "sensation  of  matter"  or 
chemaesthesis ;  the  basis  of  it  is  the  mutual  relation  of 
the  chemical  elements  which  we  describe  as  chemical 
affinity.  In  this  affinity  we  have  the  play  of  attractive 
forces  which  lie  in  the  nature  of  the  elements  them- 
selves, especially  in  the  peculiar  properties  of  their  con- 
stituent atoms;  and  this  cannot  be  explained  unless 
we  ascribe  unconscious  sensation  (in  the  widest  sense) 
to  the  atoms,  an  inherent  feeling  of  pleasure  and  the 
reverse,  which  they  experience  in  the  contact  of  other 
atoms  (the  "loves  and  hatreds  of  the  elements"  of 
Empedocles). 

The  numbers  of  different  stimuli  that  act  chemically 
on  the  plasm  and  excite  its  "sensation  of  matter"  may 
be  divided  into  two  groups — external  and  internal 
stimuli.  The  latter  lie  within  the  organism  itself,  and 
cause  the  internal  "organic  sensations";  the  former  are 
in  the  outer  world,  and  are  felt  as  taste,  smell,  sex- 
impulse,  etc.  In  the  higher  animals  special  chemical 
sense-organs  have  been  developed  for  these  chemical 
stimuli.  As  these  are  well  known  to  us  from  our  own 
human  experience,  and  comparative  physiology  shows 
us  the  same  structures  in  the  higher  animals,  we  will 
deal  first  with  them.  In  general  the  same  law  holds  for 
these  external  chemical  stimuli  as  for  optical  and 
thermic  stimuli;  we  can  recognize  a  maximum  limit  of 

302 


SENSATION 

their  action,  a  minimum  below  which  they  fail  to 
stimulate,  and  an  optimum  or  stage  in  which  their 
influence  is  strongest. 

The  important  part  played  in  human  life  by  taste  and 
the  pleasure  associated  with  it  is  well  known.  The  careful 
choice  and  preparation  of  savory  food — which  has  be- 
come an  art  in  gastronomy  and  a  branch  of  practical  phi- 
losophy in  gastrosophy — was  just  as  important  two  thou- 
sand years  ago  with  the  Greeks  and  Romans  as  it  is  to-day 
in  royal  banquets  or  the  Lucullic  dinners  of  millionaires. 
The  excitement  that  we  see  associated  with  this  refined 
combination  of  rich  foods  and  drinks,  and  that  finds 
expression  in  so  many  speeches  and  toasts,  has  its  philo- 
sophic root  in  the  harmony  of  gustatory  sensations  and 
the  varying  play  of  stimuli  that  the  delicate  dishes  and 
wines  exercise  on  the  organs  of  taste,  the  tongue  and 
palate.  The  microscopic  organs  of  these  parts  of  the 
mouth  are  the  gustatory  papillae — cup-shaped  structures, 
covered  with  spindle-shaped  "taste-cells,"  and  having  a 
narrow  opening  into  the  cavity  of  the  mouth.  When  sapid 
matters,  drinks  and  fluid  or  loose  particles  of  food,  touch 
the  taste-cells,  they  excite  the  fine  terminal  branchlets  of 
the  gustatory  nerve  which  enters  the  cells.  As  we  find 
that  there  are  similar  structures  in  most  of  the  higher 
animals,  and  that  they  also  choose  their  food  with  some 
care,  we  may  confidently  assume  that  they  have  sensa- 
tions of  taste  like  man.  However,  no  trace  of  this  is 
found  in  many  of  the  lower  animals;  in  these  cases  it  is 
impossible  to  lay  down  a  line  of  demarcation  between 
taste  and  smell. 

In  man  and  the  higher  air-breathing  vertebrates  the 
seat  of  the  sense  of  smell  is  in  the  nostrils;  in  man  it  is 
especially  that  part  of  the  mucous  lining  of  the  nasal 
cavity  which  we  call  the  "olfactory  region"  (the  upper- 
most part  of  the  nasal  dividing  wall,  the  superior  and 
middle  meatus).     It  is  necessary  for  a  sensation  of  smell 

3^^ 


THE    WONDERS    OF    LIFE 

that  the  odorous  matter,  or  olfactory  stimuH,  be  brought 
in  a  finely  divided  condition  over  the  moist  olfactory 
membranes.  When  they  touch  the  olfactory  cells — 
slender,  rod-shaped  cells  with  very  fine  hairs  at  the  free 
end — they  excite  the  ends  of  the  olfactory  nerve  which 
are  connected  with  the  cells. 

In  many  animals,  especially  mammals,  the  sense  of 
smell  has  a  much  more  important  part  in  life  than  it  has 
in  man,  in  whom  it  is  relatively  feeble.  It  is  well 
known  that  dogs  and  other  carnivora,  and  even  ungulates, 
have  a  much  keener  smell.  In  these  cases  the  nasal 
cavity,  which  is  the  seat  of  the  sense,  is  much  larger, 
and  the  muscles  in  it  are  much  stronger.  The  nostrils 
of  the  air-breathing  vertebrates  have  been  developed 
from  a  pair  of  open  nasal  depressions  in  the  skin  of  the 
fish's  head.  But  in  these  aquatic  vertebrates  the 
chemical  action  of  the  olfactory  stimuli  must  be  of  a 
different  character,  like  the  sensation  of  taste.  The 
odorous  matter  is,  in  these  cases,  brought  into  contact 
with  the  olfactory  membrane  in  a  liquid  form  (in  which 
condition  it  is  not  perceptible  to  man).  In  fact,  the 
division  between  the  senses  of  smell  and  taste  disappears 
altogether  in  the  lower  animals.  These  two  "chemical 
senses"  are  closely  related,  and  have  a  common  feature 
in  the  direct  chemical  action  of  the  stimulus  on  the 
sensitive  part  of  the  skin. 

A  chemical  sensation  of  matter  that  corresponds 
completely  to  the  real  taste-sensation  in  the  higher 
animals  is  found  in  some  of  the  higher  carnivorous 
plants.  The  leaves  of  the  sun-dew  (drosera  rotundifolia) 
are  very  sensitive  insect-traps,  and  are  armed  at  the 
edge  with  knob-like  tentacles,  sticky  hairs  that  secrete 
an  acid,  flesh-digesting  juice.  When  a  solid  body  (but 
not  a  raindrop)  touches  the  surface  of  the  leaf  the 
stimulus  acts  in  such  a  way  on  the  tentacle  heads  as  to 
contract  the  leaf.     But  the  acid  fluid  which  serves  for 

304 


SENSATION 

digestion,  and  corresponds  to  the  gastric  juice  in  the 
animal,  is  only  secreted  by  the  corpuscles  if  the  solid 
foreign  body  is  nitrogenous  (flesh  or  cheese).  Hence 
the  leaves  of  these  insectivorous  plants  taste  their  meat 
diet,  and  distinguish  it  from  other  solids,  to  which  they 
are  indifferent.  In  the  broader  sense,  in  fact,  we  may 
describe  the  points  of  the  roots  of  plants  as  organs  of 
taste;  they  plunge  into  the  richer  parts  of  the  earth 
which  yield  more  nourishment,  and  avoid  the  poor  parts. 
In  unicellular  plants  and  animals  the  action  of  chemical 
stimuli  is  especially  conspicuous  when  it  is  one-sided, 
and  provokes  definite  movements  in  one  particular 
direction  (chcmotaxis). 

The  movements  of  unicellular  organisms  that  are 
provoked  by  chemical  stimuli  and  are  known  as  chemo- 
tropism  (more  recently  as  chcmotaxis)  are  particularly 
interesting  because  they  show  the  existence  of  a  chemical 
sensitiveness,  somewhat  resembling  taste  or  smell,  in  the 
lowest  organisms,  and  even  in  the  homogeneous  plasm 
of  the  monera.  Repeated  experiments  of  Wilhelm 
Engelmann,  Max  Verworn,  and  others,  have  shown  that 
many  bacteria,  diatomes,  infusoria,  rhizopods,  and  other 
protists,  have  a  similar  sense  of  taste;  they  move 
towards  certain  acids  (for  instance,  a  drop  of  malic  acid) 
or  a  bubble  of  oxygen  that  lies  on  one  side  of  the  drop  of 
water  in  which  the  protists  are  under  the  microscope. 
Many  pathogenetic  bacteria  secrete  poisonous  sub- 
stances which  are  very  injurious  to  the  human  frame. 
The  active  white  blood-cells,  leucocytes,  in  the  human 
blood  have  a  special  "taste"  for  these  bacteria-poisons, 
and  concentrate  in  large  quantities,  by  means  of  their 
amoeboid  movements,  at  those  parts  of  the  body  where 
they  are  secreted.  If  the  leucocytes  prove  the  stronger 
in  their  struggle  with  the  bacteria,  they  destroy  them, 
and  in  this  way  they  act  as  sanitary  officers  in  keeping 
poisonous  infection  out  of  our  organism.  But  if  the 
ao  305 


THE    WONDERS    OF    LIFE 

bacteria  win  the  battle,  they  are  transported  into 
other  parts  of  the  body  by  the  leucocytes;  they  dis- 
tinguish their  plasm  by  taste,  and  may  cause  a  deadly 
infection. 

We  have  a  particularly  interesting  and  important 
species  of  chemical  irritation  in  the  mutual  attraction  of 
the  two  sex-cells,  to  which  I  gave  the  name  of  chemo- 
tropism  thirty  years  ago,  and  which  I  described  as  the 
earliest  phylogenetic  source  of  sexual  love  (see  the 
Anthropogeny,  chapters  vii.  and  xxix.).  The  remarkable 
phenomena  of  impregnation,  the  most  important  of  all 
the  processes  of  sexual  generation,  consist  in  the  coales- 
cence of  the  female  ovum  and  the  male  sperm-cell. 
This  could  not  take  place  if  the  two  cells  had  not  a 
sensation  of  their  respective  chemical  constitution  and 
disposition  for  union;  they  come  together  under  this 
impulse.  This  sexual  affinity  is  found  at  the  lowest 
stages  of  plant  life,  in  the  protophyta  and  algae.  With 
these  both  cells — the  smaller  male  microgameta  and  the 
larger  female  macrogameta — are  often  mobile,  and  swim 
about  in  order  to  effect  a  union.  In  the  higher  plants 
and  animals  only  the  small  male  cell  is  mobile  as  a  rule, 
and  swims  towards  the  large  immobile  ovum  in  order  to 
blend  with  it.  The  sensation  that  impels  it  is  of  a 
chemical  nature,  alHed  to  taste  and  smell.  This  has 
been  proved  by  the  splendid  experiments  of  Pfeffer,  who 
showed  that  the  male  ciliated  cells  of  ferns  are  attracted 
by  malic  acid,  and  those  of  the  mosses  by  cane-sugar, 
just  in  the  same  way  as  by  the  exhalation  from  the 
female  ovum.  Conception  depends  on  exactly  the  same 
erotic  chemotropism  in  the  fertilization  of  all  the  higher 
organisms. 

Erotic  chemotropism  must  be  regarded  as  a  general 
sense-function  of  the  sexual  cells  in  all  amphigonous 
organisms,  but  in  the  higher  organisms  special  forms 
of  the   sex -sense,  connected  with  specific  organs,  are 

306 


SENSATION 

developed ;  as  the  source  of  sexual  love  they  play  a  most 
important  part  in  the  life  of  many  of  the  histona.  In 
man  and  most  of  the  higher  animals  these  feelings  of 
love  are  associated  with  the  highest  features  of  psychic 
life,  and  have  led  to  the  formation  of  some  most  remark- 
able customs,  instincts,  and  passions.  Wilhelm  Bolsche 
has  given  us  an  admirable  selection  from  this  infinitely 
rich  and  attractive  realm  in  his  famous  Lijc  of  Love  in 
Nature  (1903).  It  is  well  known  that  this  sexual  sense  as 
we  have  it  in  man  has  been  developed  from  the  nearest 
related  mammals,  the  apes.  But  while  it  offers  a  shame- 
less and  repulsive  spectacle  in  many  of  the  apes,  it  has 
been  greatly  ennobled  and  refined  in  man  in  the  develop- 
ment of  civilization.  However,  the  sexual  sense-organs 
and  their  specific  energy  have  remained  the  same.  In 
the  vertebrates  and  the  articulates  and  many  other 
metazoa  the  copulative  organs  are  equipped  with  special 
cell-forms  (voluptuous  particles),  which  are  the  seat  of 
intensely  pleasurable  feelings  (see  the  Anthropogciiy, 
chapter  xxix.,  plate  30).  The  pubic  hairs  which  clothe 
the  JUGus  Veneris  are  also  delicate  organs  of  the  sex-sense, 
and  so  are  the  tactile  hairs  about  the  mouth.  In  these 
cases  the  correlation  between  the  sensitive  forms  of 
energy  in  the  copulative  organs  and  the  psychic  functions 
of  the  central  nervous  system  has  been  remarkably 
developed.  Moreover,  a  large  part  of  the  rest  of  the  skin 
may  co-operate  as  a  secondary  organ  of  the  sex-sense,  as 
is  seen  in  the  effect  of  caressing,  stroking,  embracing, 
kissing,  etc.  Goethe,  at  once  the  greatest  lyric  poet  and 
the  subtlest  and  profoundest  monistic  philosopher  of 
Germanv,  has  given  unrivalled  expression  to  this  sensual, 
yet  supersensual,  basis  of  sexual  love.  Ontogeny  teaches 
unmistakably  that  its  elementary  organs,  the  epideniiic 
cells,  develop  entirely  from  the  ectoderm. 

By  "organic  sensations"  modem  physiology-  under- 
stands the  perception  of  certain  internal  bodily  states, 

307 


THE    WONDERS    OF    LIFE 

which  are  mostly  brought  about  by  chemical  stimuli  (to 
a  small  extent  by  mechanical  and  other  irritation)  in  the 
organs  themselves.  As  subjective  feelings  of  the  or- 
ganism itself  these  states  are  most  aptly  called  "feelings" 
— the  positive  states,  pleasure,  comfort,  delight;  the 
negative,  discomfort,  pain,  etc.  These  organic  sensa- 
tions (also  called  common  sensations  or  feelings)  are  of 
great  importance  for  the  self-regulation  of  the  complicat- 
ed organism.  To  the  positive  organic  sensations  belong 
not  only  the  bodily  feeling  of  satiety,  repose,  or  comfort, 
but  also  the  psychic  feelings  of  joy,  good  humor,  mental 
rest,  etc.  Among  negative  common  feelings  we  have 
not  only  hunger  and  thirst,  bodily  fatigue,  bodily 
pain,  sea-sickness,  etc.,  but  also  mental  strain,  vertigo, 
bad  humor,  and  so  on.  Between  the  two  groups  we 
have  the  third  category  of  neutral  organic  sensations, 
which  involve  neither  pleasure  nor  pain,  but  merely  the 
perception  of  certain  internal  conditions,  such  as  mus- 
cular strain  (in  lifting  heavy  objects),  the  disposal  of  the 
limbs  (in  crossing  the  legs),  and  so  on. 

Chemical  sensation  is  just  as  general  and  important  in 
organic  nature  as  in  the  life  of  organisms.  In  this  case 
it  is  nothing  less  than  the  basis  of  chemical  affinity.  No 
chemical  process  can  be  thoroughly  understood  unless  we 
attribute  a  mutual  sensation  to  the  atoms,  and  explain 
their  combination  as  due  to  a  feeling  of  pleasure  and 
their  separation  to  a  feeling  of  displeasure.  The  great 
Empedocles  (fifth  century  b.c.)  explained  the  origin  of 
all  things  long  ago  by  the  various  combination  of  pure 
elements,  the  interaction  of  love  (attraction)  and  hate 
(repulsion).  This  attraction  or  repulsion  is,  of  course, 
unconscious,  just  as  in  the  instincts  of  plants  and 
animals.  If  one  prefers  to  avoid  the  term  "sensation," 
it  may  be  called  "feeling"  (cssthesis),  while  the  (involun- 
tary) movement  it  provokes  may  be  called  "inclination  " 
{tropesis),  and  the  capacity  for  the  latter   "tropism" 

308 


SENSATION 

(more  recently  taxis,  cf.  chapter  xii.  of  the  Riddle).  We 
may  illustrate  it  from  the  simplest  case  of  chemical  com- 
bination. When  we  rub  together  sulphur  and  mer- 
cury, two  totally  different  elements,  the  atoms  of  the 
finely  divided  matter  combine  and  form  a  third  and 
different  chemical  body,  cinnabar.  How  would  this 
simple  synthesis  be  possible  unless  the  two  elements  feel 
each  other,  move  towards  each  other,  and  then  unite  ? 
We  find  universally  distributed  in  nature  the  sensation 
of  the  mechanical  stimulus  of  gravitation,  the  most 
comprehensive  statement  of  wdiich  is  given  in  Newton's 
law  of  gravity.  According  to  this  fundamental  and  all- 
ruling  law,  any  two  particles  of  matter  are  attracted  in 
direct  proportion  to  their  mass  and  inverse  proportion 
to  the  square  of  their  distance.  This  form  of  attraction, 
also,  can  be  traced  to  a  "sensation  of  matter"  in  the 
mutually  attracting  atoms.  The  local  sensation  that 
any  body  provokes  by  contact  with  the  surface  of  an 
organism  is  felt  as  pressure  (baros).  A  stimulus  that 
causes  this  pressure  alone  brings  about  a  counter-press- 
ure as  a  reaction,  and  an  effort  to  neutralize  it,  the 
pressure-movement  {harotaxis  or  barotropism).  Sensi- 
tiveness to  pressure  or  the  contact  of  solid  bodies  is 
found  throughout  the  organic  world;  it  can  be  proved 
experimentally  among  the  protists  as  well  as  the  histona. 
Special  sense-organs  have  been  developed  in  the  skin  of 
the  higher  animals  as  the  instruments  of  this  pressure- 
sense  (baraesthesis)  in  the  form  of  tactile  corpuscles; 
they  are  most  numerous  at  the  finger-tips  and  other 
particularly  sensitive  parts.  In  many  of  the  higher 
animals  there  is  a  fine  sense  of  touch  in  the  feelers  or 
tentacles,  or  (in  the  higher  articulates)  in  the  horns  or 
antennae.  Moreover,  these  tactile  and  prehensile  organs 
are  also  very  widely  found  among  the  higher  plants, 
especially  the  climbing  plants  (vines,  bryony,  etc.). 
Their  slender  creepers,  which  roll  out  spirally,  have  a 

309 


THE    WONDERS    OF    LIFE 

very  delicate  feeling  for  the  nature  of  the  supports  which 
they  embrace;  they  distinguish  between  smooth  and 
rough,  thick  and  thin  supports,  and  prefer  the  latter. 
Many  of  the  higher  plants,  which  are  particularly  sensi- 
tive to  pressure,  have,  to  an  extent,  special  organs  of 
touch  (tentacles),  and  reveal  this  by  the  movements  of 
their  leaves  (the  sensitive  plants,  mimosa,  dionasa,  oxalis). 
But  even  among  the  unicellular  protists  we  find  that  the 
contact  of  solid  bodies  has  an  irritating  effect,  the  per- 
ception of  which  provokes  corresponding  movements 
{thigmotaxis  or  thigmotropismiis).  A  peculiar  form  of 
pressure-sensation  is  produced  in  many  organisms  by 
the  flow  of  liquids;  in  the  mycetozoa,  for  instance,  it 
provokes  counter-movements  {rheotaxis,  rheotropismus) , 
as  Ernst  Strahl  showed  by  his  experiments  on  cBthelium 
septicum. 

We  have  an  interesting  analogy  to  the  thigmotaxis  of 
the  viscous  living  plasm  in  the  elasticity  of  solid  inor- 
ganic bodies,  such  as  an  elastic  steel-rod.  In  virtue  of 
its  springy  nature,  the  elastic  rod  reacts  on  the  pressure 
of  force  that  has  bent  it,  and  endeavors  to  regain  its 
former  position.  The  spiral  spring  sets  the  works  of  the 
clock  in  motion  in  virtue  of  its  elasticity. 

A  very  important  part  is  played  in  botany  by  the 
action  of  gravitation  on  the  growth  of  plants.  The 
attraction  towards  the  centre  of  the  earth  causes  the 
positively  geotropic  roots  to  grow  vertically  into  the 
earth,  while  the  negatively  geotropic  stalk  pushes  out 
in  the  opposite  direction.  This  applies  also  to  a  number 
of  stationary  animals  which  are  attached  to  the  ground 
by  roots,  such  as  polyps,  corals,  bryozoa,  etc.  And  even 
the  locomotion  of  free  animals,  the  disposition  of  their 
bodies  to  the  ground,  the  position  and  posture  of  their 
limbs,  etc.,  is  determined  partly  by  the  feeling  of 
gravitation,  and  partly  by  adaptation  to  certain  functions 
which  resist  this,  as  in  running,  swimming,  and  so  on. 

310 


SENSATION 

All  these  geotropic  sensations  belong  to  the  same  group 
of  barotactile  phenomena,  as  the  fall  of  a  stone  or  any 
other  effect  of  gravitation  that  depends  on  an  inorganic 
feeling  of  attraction. 

As  a  result  of  these  adaptations,  we  find  a  distinct 
sense  of  space  developed  in  the  higher,  free-moving 
animals.  The  feeling  of  the  three  dimensions  of  space 
becomes  an  important  means  of  orientation,  and  in  the 
vertebrates,  from  the  fishes  up  to  man,  the  three  spiral 
canals  in  the  inner  ear  are  developed  as  special  organs 
of  this.  These  three  semicircular  canals,  which  lie 
vertically  to  each  other  in  the  three  dimensions  of  space, 
are  the  organs  of  the  sensation  that  guides  the  move- 
ments of  the  head,  and,  in  relation  to  this,  for  the 
normal  posture  of  the  body  and  the  feeling  of  equilibrium. 
If  the  three  spiral  canals  are  destroyed,  the  equilibrium 
is  lost;  the  body  totters  and  falls.  Hence,  these  organs 
are  not  of  an  acoustic,  but  a  static  or  geotactic  charac- 
ter; and  the  same  may  be  said  of  the  so-called  "auditory 
vesicles"  of  many  of  the  lower  animals — round  vesicles 
which  contain  a  liquid  and  a  solid  body,  the  otolith. 
When  this  body  changes  its  position  with  the  change 
of  posture  of  the  whole  frame,  it  presses  on  the  fine 
auditory  hairs,  or  delicate  terminations  of  the  auscultory 
nerve,  which  enters  the  vesicle.  In  fact,  the  sense  of 
equilibrium  is  often  combined  with  the  sense  of  hearing. 

The  perception  of  noises  and  tones,  which  we  call 
hearing,  is  restricted  to  a  section  of  the  higher,  free- 
moving  animals;  if,  that  is  to  say,  the  above-mentioned 
"auditory  vesicles"  in  the  lower  animals  do  not  have 
acoustic  as  well  as  static  sensations.  The  specific  sensa- 
tion of  hearing  is  due  to  vibration  of  the  medium  in 
which  the  animal  lives  (air  or  water),  or  to  vibrations  of 
solid  bodies  (such  as  tuning-forks)  which  are  brought 
into  touch  with  them.  If  the  vibrations  are  irregular, 
they  are  felt  as  "noises";  if  regular,  they  are  heard  as 


THE    WONDERS    OF    LIFE 

"tones"  or  notes;  when  a  number  of  tones  together 
(fundamental  and  over-tones)  excite  a  complex  sensa- 
tion, we  have  "timbre."  The  vibrations  of  the  sounding 
body  are  borne  to  the  auditory  cells,  which  represent 
the  terminal  extensions  of  the  auscultory  nerve.  The 
specific  sensation  of  hearing  can,  therefore,  be  traced 
originally  to  the  sense  of  pressure,  from  which  it  has 
been  evolved.  As  the  organ  of  hearing  is,  like  the  eye, 
one  of  the  principal  instruments  of  the  higher  mental 
life,  and  as  the  refined  musical  hearing  of  civilized  man 
is  often  taken  to  be  a  metaphysical  power  of  the  soul,  it 
is  important  to  note  that  here  again  the  starting-point 
was  purely  physical — that  is  to  say,  it  can  be  traced  to 
the  sense  of  pressure  of  matter,  or  gravitation. 

The  great  importance  of  electricity  as  an  agency  in 
nature,  both  organic  and  inorganic,  has  only  lately  been 
fully  appreciated.  Electric  changes  are  connected  with 
many  (if  not,  as  is  now  supposed,  with  all)  chemical  and 
optical  processes.  Man  himself  and  most  of  the  higher 
animals  have  no  electric  organs  (apart  from  the  eye), 
and  no  sense-organs  that  experience  a  specific  electric 
sensation.  It  is  probably  otherwise  with  many  of  the 
lower  animals,  especially  those  that  develop  free  elec- 
tricity, such  as  the  electric  fishes.  The  larvas  of  frogs 
and  embryos  of  fishes,  if  put  in  a  vessel  of  water  through 
which  a  galvanic  current  is  sent,  place  themselves  when 
it  is  closed  with  their  longitudinal  axis  in  the  direction 
of  the  current,  with  the  head  directed  to  the  anode  and 
the  tail  to  the  cathode  (Hermann).  Again,  the  luminous 
sea-animals  which  cause  the  beautiful  phenomenon  of 
the  illumination  of  the  sea,  and  the  glow-worms  and 
other  luminous  organisms,  have  probably  an  unconscious 
feeling  of  the  flow  of  electric  energy  associated  with 
these  phenomena.  Many  plants  show  a  direct  reaction 
to  electric  stimuli;  when,  for  instance,  we  send  a  con- 
stant galvanic  current  for  some  time  through  the  points 

312 


SENSATION 

of  their  roots  (very  sensitive  organs,  compared  by 
Darwin  to  the  brain  of  the  animal),  they  bend  towards 
the  cathode. 

Many  of  the  protists  are  very  sensitive  to  electric 
currents,  as  Max  Verworn  especially  proved  by  a  series 
of  beautiful  experiments.  Most  of  the  ciliated  infusoria 
and  many  of  the  rhizopods  (aDurba)  are  cathodically 
sensitive  or  negatively  galvanotactic.  When  we  send  a 
constant  electric  current  through  a  drop  of  water  in 
which  thousands  of  paramoociiDii  are  moving  about,  all 
the  infusoria  swim  at  once,  with  the  anterior  pole  of  the 
body  foremost,  towards  the  cathode  or  negative  pole; 
they  accumulate  about  it  in  great  crowds.  If  the  direc- 
tion of  the  current  is  now  changed,  the  whole  swarm  at 
once  make  in  the  opposite  direction  for  the  new  cathode. 
Most  of  the  flagellate  infusoria  do  just  the  reverse;  they 
are  anodically  sensitive  or  positively  galvanotactic.  In  a 
drop  of  water,  in  which  swarms  of  polytoma  are  moving 
about,  all  the  cells  swim  at  once  towards  the  anode  or 
positive  pole,  when  an  electric  current  is  sent  through. 
The  opposite  galvanotropic  behavior  of  these  two 
groups  of  infusoria  in  a  drop  of  water,  in  which  they  are 
mixed  together,  is  very  interesting;  as  soon  as  a  constant 
stream  enters  it,  the  ciUata  fly  to  the  cathode  and  the 
flagellata  to  the  anode.  When  the  current  is  reversed 
the  two  swarms  rush  at  each  other  like  hostile  armies, 
cross  in  the  middle  of  the  drop,  and  gather  at  the  op- 
posite poles.  These  and  other  phenomena  of  galvanic 
sensation  show  clearly  that  the  living  plasm  is  subject  to 
the  same  physical  laws  as  the  water  that  is  decomposed 
into  hydrogen  and  oxygen  by  an  electric  current.  Both 
elements  feci  the  opposite  electricities. 

SCALE   OF   SENSATION   AND   IRRITABILITY 

ist   Stage:  Sensation  of  Atoms.     Atlinity  of  the  elements  in 
every  chemical  combination. 


THE    WONDERS    OF    LIFE 

2d  Stage:  Sensation  of  Molecules  (groups  of  atoms) :  in  the 
attraction  and  repulsion  of  molecules  (positive  and  nega- 
tive electricity,  etc.). 
3d  Stage:  Sensation  of  Plastidules  (micella,  biogens,  or 
plasma-molecules) :  in  the  simplest  vital  process  of  the 
monera  (chromacea  and  bacteria). 

4th  Stage:  Sensation  of  Cells:  irritability  of  the  unicellular 
protists  (protophyta  and  protozoa) :  erotic  chemotropism 
connected  with  the  nucleus  and  trophic  with  the  cell-body. 

5th  Stage:  Sensation  of  Ccenobia  (volvox,  magosphaera) . 
With  the  formation  of  cell-communities  we  have  associa- 
tion of  sensations  (individual  feeling  on  the  part  of  the 
social  cells  together  with  common  feeling  on  the  part  of 
the  community). 

6th  Stage:  Sensation  of  the  Lower  Plants.  In  the  meta- 
phyta  or  tissue-plants  all  the  cells  are  still  equally  sensitive 
at  the  lower  stages:  there  are  no  special  sense-organs. 

7th  Stage:  Sensation  of  the  Higher  Plants.  In  the  higher 
metaphyta  specially  sensitive  cells,  or  groups  of  cells,  with 
a  specific  energy,  are  developed  at  certain  points:  sense- 
organs.. 

8th  Stage:  Sensation  of  the  Lower  Metazoa,  without 
differentiated  nerves  or  sense-organs.  Lower  ccelenteria: 
sponges,  polyps,  platodaria. 

9th  Stage:  Sensation  of  the  Higher  Metazoa,  with  dif- 
ferentiated nerves  and  sense-organs,  but  still  without 
consciousness(?).  The  higher  ccelenteria  and  most  of  the 
coelomaria. 
loth  Stage:  Sensation  with  Dawning  Consciousness,  with 
independent  formation  of  the  phronema.  The  higher 
articulata  (spiders  and  insects)  and  vertebrates  (amphibia, 
lower  reptiles,  lower  mammals) . 
nth  Stage:   Sensation   with   Consciousness   and  Thought: 

amniotes:  higher  reptiles,  birds,  and  mammals:  savages. 
12th  Stage:  Sensation  with  Productive  Mental  Action  in 
Art  and  Science:  civilized  men.  \ 


XIV 

MENTAL  LIFE 

Mind  and  soul — Intelligence  and  reason — Pure  reason — Kant's 
dualism — Anthropology — Anthropogeny — Embryology  of 
the  mind — Mind  of  the  embryo — The  canonical  mind — 
Legal  rights  of  the  embryo — Phylogeny  of  the  mind — 
Paleontology  of  the  mind — Psyche  and  phronema — 
Mental  energy — Diseases  of  the  mind — Mental  powers — 
Conscious  and  unconscious  mental  life — Monistic  and 
dualistic  theory — Mental  life  of  the  mammals,  of  savages, 
and  of  civilized  and  educated  people. 

THE  greatest  and  most  commanding  of  all  the 
wonders  of  life  is  unquestionably  the  mind  of  man. 
That  function  of  the  human  organism,  to  which  we  give 
the  name  of  "mind,"  is  not  only  the  chief  source  of  all 
the  higher  enjoyment  of  life  for  ourselves,  but  it  is  also 
the  power  that  most  effectually  separates  man  from  the 
brute  according  to  conventional  beliefs.  Hence  it  is 
supremely  important  for  our  biological  philosophy  to 
devote  a  few  careful  pages  to  the  study  of  its  nature,  its 
origin  and  development,  and  its  relation  to  the  body. 

At  the  very  outset  of  our  psychological  inquiry  we  are 
met  by  the  difficulty  of  giving  a  clear  definition  of 
"mind,"  and  distinguishing  it  from  "soul."  Both  ideas 
are  extremely  ambiguous:  their  content  and  connotation 
are  described  in  the  most  various  ways  by  the  represent- 
atives of  science.  Generally  speaking,  we  mean  by  mind 
that  part  of  the  life  of  the  soul  which  is  connected  with 
consciousness  and  thought,  and  is,  therefore,  only  found 
in  the  higher  animals  which  have  intelligence  and  reason. 

315 


THE    WONDERS    OF    LIFE 

In  a  narrower  sense  reason  is  regarded  as  the  proper 
function  of  mind,  and  as  the  essential  prerogative  of  man 
in  the  animal  world.  In  this  sense  Kant  especially  has 
done  much  to  strengthen  the  prevailing  conception  of 
mental  action,  and  has,  by  his  Critique  of  Pure  Reason, 
converted  philosophy  into  a  mere  "science  of  reason." 
In  consequence  of  this  conception,  which  still  prevails 
widely  in  scientific  circles,  we  will  first  study  the  mental 
life  in  the  action  of  reason,  and  try  to  form  a  clear  idea 
of  this  great  wonder  of  life. 

Psychologists  and  metaphysicians  are  of  very  varied 
opinions  as  to  the  difference  between  intelligence  and 
reason.  Schopenhauer,  for  instance,  considers  causality 
to  be  the  sole  function  of  intelligence,  and  the  formation 
of  concepts  to  be  the  province  of  reason;  in  his  opinion 
the  latter  power  alone  marks  off  man  from  the  brute. 
However,  the  power  of  abstraction,  which  collects  the 
common  features  in  a  number  of  different  presentations, 
is  also  found  in  the  higher  animals.  Intelligent  dogs  not 
only  discriminate  between  individual  men,  cats,  etc., 
according  as  they  are  sympathetic  or  the  reverse,  but 
they  have  a  general  idea  of  man  or  cat,  and  behave  very 
differently  towards  the  two.  On  the  other  hand,  the 
power  of  forming  concepts  is  still  so  slight  in  uncivilized 
races  that  it  rises  but  little  above  the  mind  of  dogs, 
horses,  etc.;  the  mental  interval  between  them  and 
civilized  man  is  extremely  wide.  However,  a  long  scale 
of  reason  unites  the  various  stages  of  association  of 
presentations  which  lead  up  to  the  formation  of  concepts; 
it  is  quite  impossible  to  lay  down  a  strict  line  of  demarca- 
tion between  the  lower  and  higher  mental  functions  of 
animals,  or  between  the  latter  and  reason.  Hence  the 
distinction  between  the  two  cerebral  functions  is  only 
relative;  the  intelligence  comprises  the  narrower  circle 
of  concrete  and  more  proximate  associations,  while  rea- 
son deals  with  the  wider  sphere  of  abstract  and  more 

316 


MENTAL    LIFE 

comprehensive  groups  of  association.  In  the  scientific 
hfe  of  the  mind,  therefore,  the  intelligence  is  always 
occupied  with  empirical  investigation,  and  reason  with 
speculative  knowledge.  But  the  two  faculties  are 
equally  functions  of  the  phronema,  and  depend  on  the 
normal  anatomic  and  chemical  condition  of  this  organ 
of  thought. 

Since  Kant  won  so  great  a  prominence  in  modern 
philosophy  for  the  idea  of  pure  reason  by  his  famous 
Critique  (1781),  it  has  been  much  discussed,  especially  in 
the  modern  metaphysical  theory  of  knowledge.  It  has, 
however,  like  all  other  ideas,  undergone  considerable 
changes  of  meaning  in  the  course  of  time.  Kant  himself 
at  first  understood  by  pure  reason  "reason  independent 
of  all  experience."  But  impartial  modern  psychology 
based  on  the  physiology  of  the  brain  and  the  phylogeny 
of  its  functions,  has  shown  that  there  is  no  such  thing  as 
this  pure  a  priori  knowledge,  independent  of  all  experi- 
ence. Those  principles  of  reason  which  at  present  seem 
to  be  a  priori  in  this  sense  have  been  attained  in  virtue 
of  thousands  of  experiences.  In  so  far  as  this  is  a  ques- 
tion of  real  knowledge  of  the  truth,  Kant  himself  has 
frequently  recognized  the  point.  He  says  expressly  in 
his  Prolegomena  to  any  future  metaphysic  that  can  be 
regarded  as  Science  (1783,  p.  204):  "A  knowledge  of 
things  by  pure  reason  or  pure  intelligence  is  nothing 
but  an  empty  appearance;  only  in  experience  is  there 
truth."  In  subscribing  to  this  empirical  theory  of 
knowledge  of  Kant  I.  and  rejecting  the  transcendental 
theory  of  Kant  II.,  we  may  on  our  side  understand  by 
pure  reason  "knowledge  without  prejudices,"  free  from 
all  dogma — all  fictions  of  faith. 

The  familiar  cry  of  modern  metaphysicians,  "Return 
to  Kant,"  has  become  so  general  in  Germany  that  not 
only  nearly  all  metaphysicians — the  oihcial  representa- 
tives  of   "philosophy"    at  our  universities  —  but  also 

317 


THE    WONDERS    OF    LIFE 

many  distinguished  scientists,  regard  Kant's  dualistic 
theory  of  knowledge  as  a  necessary  condition  for  the 
attainment  of  truth.  Kant  dominated  philosophy  in 
the  nineteenth  century  much  as  Aristotle  did  in  the 
Middle  Ages.  His  authority  became  especially  powerful 
when  the  prevailing  Christian  faith  believed  that  his 
"practical  reason"  fully  supported  its  own  three  funda- 
mental dogmas — the  personality  of  God,  the  immortality 
of  the  soul,  and  the  freedom  of  the  will.  It  overlooked 
the  fact  that  Kant  had  utterly  failed  to  find  proofs  of 
these  dogmas  in  his  Critique  of  Pure  Reason.  Even 
conservative  governments  found  favorable  features  in 
this  dualistic  philosophy.  We  are,  therefore,  forced  to 
return  once  more  to  this  mischievous  system;  though 
Kant's  antinomy  of  the  two  reasons  has  now  been  refuted 
so  often  and  so  thoroughly  that  we  need  not  dwell  any 
further  on  this  point. 

Although  the  great  Konigsberg  philosopher  brought 
every  side  of  human  life  within  his  comprehensive 
sphere  of  study,  man  remained  to  him — as  he  had  been 
to  Plato  and  Aristotle.  Christ  and  Descartes — a  dual 
being,  made  up  of  a  physical  body  and  a  transcendental 
mind  or  spirit.  Comparative  anatomy  and  evolution, 
which  have  provided  the  solid  morphological  basis  of 
monistic  anthropology,  did  not  come  into  existence  until 
the  beginning  of  the  nineteenth  century;  they  were 
quite  unknown  to  Kant.  He  had,  however,  a  presenti- 
ment of  their  importance,  as  Fritz  Schultze  has  shown 
in  his  interesting  work  on  Kant  and  Darwin  (1875).  We 
find  in  various  places  expressions  which  may  be  described 
as  anticipations  of  Darwinism.  Kant  also  gave  lectures 
on  "  Pragmatic  Anthropology,"  and  studied  the  psychol- 
ogy of  races  and  peoples.  It  is  remarkable  that  he  did 
not  arrive  at  a  phylogenetic  conception  of  the  human 
mind,  and  a  recognition  of  the  possibility  of  its  evolu- 
tion from  the  mind  of  other  vertebrates.     It  is  clear  that 

318 


MENTAL    LIFE 

he  was  held  back  from  this  by  the  profound  mystic 
tendency  of  his  theory  of  reason,  and  the  dogma  of  the 
immortahty  of  the  soul,  the  freedom  of  the  will,  and  the 
categorical  imperative.  Reason  remained  in  Kant's 
view  a  transcendental  phenomenon,  and  this  dualistic 
error  had  a  great  influence  on  the  whole  structure  of  his 
philosophy.  It  must  be  remembered,  of  course,  that 
our  knowledge  of  the  psychology  of  peoples  was  then 
very  imperfect;  but  a  critical  study  of  the  facts  then 
known  should  have  sufficed  to  convince  him  of  the  lower 
and  animal  condition  of  their  minds.  If  Kant  had  had 
children,  and  followed  patiently  the  development  of  the 
child's  soul  (as  Preyer  did  a  century  later),  he  would 
hardly  have  persisted  in  his  erroneous  idea  that  reason, 
with  its  power  of  attaining  a  priori  knowledge,  is  a 
transcendental  and  supernatural  wonder  of  life,  or  a 
unique  gift  to  man  from  Heaven. 

The  root  of  the  error  is  that  Kant  had  no  idea  of  the 
natural  evolution  of  the  mind.  He  did  not  employ  the 
comparative  and  genetic  methods  to  which  we  owe  the 
chief  scientific  achievements  of  the  last  half-century. 
Kant  and  his  followers,  who  confined  themselves  almost 
exclusively  to  the  introspective  method  or  the  self-obser- 
vation of  their  own  mind,  regarded  as  the  model  of  the 
human  soul  the  highly  developed  and  versatile  mind  of 
the  philosopher,  and  disregarded  altogether  the  lower 
stages  of  mental  life  which  we  find  in  the  child  and  the 
savage. 

The  immense  advance  made  by  the  science  of  man 
in  the  second  half  of  the  nineteenth  century  cut  the 
ground  from  under  the  older  anthropology  and  the 
dualistic  system  of  Kant.  A  number  of  newly  founded 
branches  of  science  co-operated  in  the  work.  Compara- 
tive anatomy  showed  that  our  whole  complicated  frame 
resembles  that  of  the  other  mammals,  and  in  particular 
differs  only  by  slight  stages  of  growth,  and  therefore  in 

319 


THE    WONDERS    OF    LIFE 

the  details  of  the  organs,  from  that  of  the  anthropoid 
apes.  The  comparative  histology  of  the  brain  especially 
showed  that  this  is  also  true  of  the  brain,  the  real  organ 
of  mind.  From  comparative  embryology  we  learned 
that  man  develops  from  a  simple  ovum  just  like  the 
anthropoid  ape;  in  fact,  that  it  is  almost  impossible  to 
distinguish  between  the  ape  and  the  human  embryo 
even  at  a  late  stage  of  development.  Comparative 
animal  chemistry  explained  that  the  chemical  compounds 
which  build  up  our  organs,  and  the  conversions  of  energy 
which  accompany  its  metabolism,  resemble  those  in  the 
other  vertebrates.  Comparative  physiology  taught  us 
that  all  man's  vital  functions — nutrition  and  reproduc- 
tion, movement  and  sensation — can  be  traced  to  the 
same  physical  laws  in  man  as  in  all  the  other  verte- 
brates. Above  all,  the  comparative  and  experimental 
study  of  the  sense-organs  and  the  various  parts  of  the 
brain  showed  that  these  organs  of  the  m'nd  work  in  the 
same  way  in  man  as  in  the  other  primates.  Modern 
paleontology  taught  that  man  is,  it  is  true,  more  than 
a  hundred  thousand  years  old,  but  only  appeared  on 
earth  towards  the  close  of  the  Tertiary  Period.  Pre- 
historic research  and  comparative  ethnology  have  shown 
that  civilized  nations  were  preceded  by  older  and  lower 
races,  and  these  by  savages,  which  have  a  close  bodily 
and  mental  affinity  to  the  apes.  Finally,  the  reformed 
theory  of  descent  (1859)  enabled  us  to  unite  the  chief 
results  of  the  various  branches  of  anthropological  study, 
and  explain  them  phylogenetically  by  the  development 
of  man  from  other  primates  (anthropoid  apes,  cynoceph- 
ali,  lemures,  etc.).  By  this  means  a  new  and  monistic 
basis  was  provided  for  modern  anthropology;  the  posi- 
tion assigned  to  man  in  nature  by  dualistic  metaphysics 
was  shown  to  be  utterly  untenable.  I  have  attempted 
in  the  last  edition  of  my  Anthropogeny  (of  which  an 
English  edition  is  in  preparation)  to  combine  all  these 

320 


MENTAL    LIFE 

results  of  empirical  investigation  in  a  sketch  of  the 
natural  evolution  of  man,  paying  special  regard  to  em- 
bryology. I  pointed  out  in  chapters  ii.-vi.  of  the 
Riddle  how  important  a  part  of  our  monistic  philosophy 
this  phylogenetic  anthropology  is. 

The  monistic  conception  of  the  human  body  and 
mind,  which  the  theory  of  descent  has  put  on  a  zoo- 
logical basis,  was  bound  to  meet  with  the  sternest 
resistance  in  dualistic  and  metaphysical  circles.  It  was, 
however,  also  regarded  with  great  disapproval  by  many 
modern  empirical  anthropologists,  especially  those  who 
take  it  to  be  their  chief  task  to  make  as  "exact"  a 
study  as  possible  of  the  human  frame,  and  measure  and 
describe  its  various  parts.  We  might  have  expected 
these  descriptive  anthropologists  and  ethnologists  to 
extend  a  friendly  hand  to  the  new  anthropogeny,  and 
avail  themselves  of  its  leading  ideas,  in  order  to  bring 
unity  and  causal  connection  into  the  enormous  mass  of 
empirical  material  accumulated.  However,  this  took 
place  only  to  a  limited  extent,  The  majority  of  anthro- 
pologists regarded  evolution,  and  especially  the  evolution 
of  man,  as  an  undemonstrated  hypothesis.  They  con- 
fined themselves  to  accumulating  huge  masses  of  raw 
empirical  material,  without  having  any  clear  aim  or  any 
definite  questions  in  view.  This  was  chiefly  the  case  in 
Germany,  where  the  Society  of  Anthropology  and  Pre- 
historic Research  was  for  thirty  years  under  the  lead 
of  Rudolph  Virchow.  This  famous  scientist  had  won 
great  honor  in  connection  with  the  reform  of  medicine 
by  his  cellular  pathology  and  a  number  of  distinguished 
works  on  pathological  anatomy  and  histology  since  the 
middle  of  the  nineteenth  century.  But  when  he  after- 
wards (subsefjuently  to  his  removal  to  Berlin,  1856) 
devoted  himself  chiefly  to  political  and  social  questions, 
he  lost  sight  of  the  great  advance  made  in  other  branches 
of   biology.     He    comi)letely    failed    to    appreciate    its 


21 


THE    WONDERS    OF    LIFE 

greatest  achievement — the  establishment  of  the  science 
of  evolution  by  Darwin.  To  this  we  must  add  the 
psychological  metamorphosis  (similar  to  that  of  Wundt, 
Baer,  Dubois-Reymond,  and  others),  of  which  I  have 
spoken  in  the  sixth  chapter  of  the  Riddle.  The  extraor- 
dinary authority  of  Virchow,  and  the  indefatigable  zeal 
with  which  he  struggled  every  year  until  his  death 
(1903)  against  the  descent  of  man  from  other  verte- 
brates, caused  a  wide-spread  opposition  to  the  doctrine 
of  evolution.  This  was  supported  especially  by  Johan- 
nes Ranke,  of  Munich,  the  secretary  of  the  Anthro- 
pological Society.  Happily,  a  change  has  recently  set 
in.  However,  my  Anthropogeiiy  has  remained  for  thirty 
years  the  only  work  of  its  kind — namely,  a  comprehen- 
sive treatment  of  man's  ancestral  history,  especially  in 
the  light  of  embryology. 

As  I  pointed  out  in  the  eighth  and  ninth  chapters  of 
the  Riddle,  the  most  solid  foundation  of  our  monistic 
psychology  is  the  fact  that  the  human  mind  grows. 
Like  every  other  function  of  our  organism,  our  mental 
activity  exhibits  the  phenomenon  of  development  in 
two  directions,  individually  in  each  human  being  and 
phyletically  in  the  whole  race.  The  ontogeny  of  the 
mind — or  the  embryology  of  the  human  soul — brings 
before  us  in  direct  observation  the  various  stages  of 
development  through  which  the  mind  of  every  man 
passes  from  the  beginning  to  the  close  of  life.  The 
phylogeny  of  the  mind — or  the  ancestral  history  of  the 
human  soul — does  not  afford  us  this  direct  observation ; 
it  can  only  be  deduced  by  a  comparison  and  synthesis  of 
the  historical  indications  which  are  supplied  by  history 
and  prehistoric  research  on  the  one  hand,  and  the 
critical  study  of  the  various  stages  of  mental  life  in 
savages  and  the  higher  vertebrates  on  the  other.  In 
this  the  biogenetic  law  is  used  with  great  success  (chapter 
xvi.). 

322 


MENTAL    LIFE 

As  everybody  knows,  the  new-born  child  shows  as  yet 
no  trace  of  mind  or  reason  or  consciousness;  these 
functions  are  wanting  in  it  as  completely  as  in  the 
embryo  from  which  it  has  been  developed  during  the 
nine  months  in  the  mother's  womb.  Even  in  the  ninth 
month,  when  most  of  the  organs  of  the  human  embryo 
are  formed  and  arranged  as  they  appear  later,  there  is 
no  more  trace  of  mind  in  its  psychic  life  than  in  the 
ovum  and  spermatozoon  from  which  it  was  evolved. 
The  moment  in  which  these  sexual  cells  unite  marks 
precisely  the  real  commencement  of  individual  existence, 
and  therefore  of  the  soul  also  (as  a  potential  function  of 
the  plasm).  But  the  mind  proper — or  reason,  the  high- 
er conscious  function  of  the  soul — only  develops,  slowly 
and  gradually,  long  after  birth.  As  Flechsig  has  shown 
anatomically,  the  cortex  in  the  new-bom  child  is  not  yet 
organized  or  capable  of  functioning.  Rational  conscious- 
ness is  even  impossible  for  the  child  when  it  begins  to 
speak;  it  reveals  itself  for  the  first  time  (after  the  first 
year)  at  the  moment  when  the  child  speaks  of  itself,  not 
in  the  third  person,  but  as  "L"  With  this  self -con- 
sciousness comes  also  the  antithesis  of  the  individual  to 
the  outer  world,  or  world-consciousness.  This  is  the 
real  beginning  of  mental  life. 

In  defining  the  appearance  of  the  individual  mind  by 
the  awakening  of  self-consciousness,  we  make  it  possible 
to  distinguish,  from  the  monistic  physiological  point  of 
view,  between  "soul"  (psyche)  and  "spirit"  {p>icnma). 
There  is  a  soul  even  in  the  maternal  ovum  and  the  pa- 
ternal spermatozoon  (cf.  chapter  xi.);  there  is  an  indi- 
vidual soul  in  the  stem-cell  (cyttda)  which  arises  at  con- 
ception by  the  blending  of  the  parent  cells.  But  the 
mind  proper,  the  thinking  reason,  develops  out  of  the 
animal  intelligence  (or  earlier  instincts)  of  the  child  only 
with  the  consciousness  of  its  personality  as  opposed  to 
the  outer  world.     At  the  same  time  the  child  reaches  the 

323 


THE    WONDERS    OF    LIFE 

higher  stage  of  personality,  which  law  has  for  a  long 
time  taken  under  its  protection  and  made  morally  re- 
sponsible to  society  by  education.  This  shows  how  er- 
roneous and  untenable,  from  the  physiological  point  of 
view,  are  the  ideas  still  embodied  in  our  code  as  to  the 
psychic  life  and  the  mind  of  the  embryo  and  the  new- 
born infant.  They  came  mostly  from  the  canon  law  of 
the  Catholic  Church. 

The  dualistic  ideas  of  the  soul  of  the  human  embry^o 
which  were  taught  by  the  Church  in  the  Middle  Ages  are 
particularly  interesting  from  the  psychological  point  of 
view;  and  at  the  same  time  they  are  of  great  practical 
importance  even  in  our  own  day,  since  many  of  their 
moral  consequences  form  an  important  element  in  canon 
law,  and  have  passed  from  this  into  civil  law.  This 
influential  canon  law  was  formed  under  ecclesiastical 
authority  from  the  decisions  of  Church  councils  and  the 
decretals  of  the  popes.  It  is,  like  most  of  the  dogmas 
and  decrees  which  civilization  owes  to  this  powerful 
hierarchy,  a  curious  tissue  of  old  traditions  and  new 
fictions,  political  dogmas,  and  crass  superstition.  It  is 
directed  to  the  despotic  ruling  of  the  uneducated  masses 
and  the  exclusive  dominion  of  the  Church — a  Church 
that  calls  itself  Christian  while  thus  acting  as  the  very 
reverse  of  pure  Christianity.  The  canon  law  takes  its 
name  from  the  dogmatic  rules  (or  canons)  of  the  Church. 
They  involuntarily  suggest  the  metal  tubes  which  are  so 
often  the  ultima  ratio  regis  in  the  wars  of  Christian 
nations.  The  canonical  regulations  of  the  Church,  as 
implements  of  a  crude  spiritual  despotism,  have  no  more 
to  do  with  the  ethical  laws  of  pure  reason  than  the  can- 
nons of  secular  authorities  have  as  naked  organs  of 
physical  force.  We  might  write  the  motto.  Ultima  ratio 
ecclesicB  (the  last  argument  of  the  Church),  over  the 
sacred  Corpus  Juris  Canonici.  A  collection  of  later 
papal  decretals  which  forms  an  appendix  to  the  books 

324 


MENTAL    LIFE 

of  canon  law  was  very  happily  given  the  official  title 
of  Extravagaiitcs.  Among  the  "extravagant"  nonsense 
which  the  papacy  included  in  canon  law  as  a  moral 
code  for  believers  is  its  view  of  the  psychic  life  of  the 
embryo.  The  "immortal  soul"  is  supposed  to  enter  the 
soulless  embryo  only  several  weeks  after  conception. 
As  theologians  and  metaphysicians  are  very  much  di- 
vided as  to  the  period  of  this  entrance  of  the  soul,  and 
know  nothing  about  the  structure  of  the  embryo  and  its 
development,  we  will  only  recall  the  fact  that  the  human 
foetus  cannot  be  distinguished  from  that  of  the  anthro- 
poid ape  and  other  mammals  even  in  the  sixth  week  of 
its  development.  The  outline  of  the  five  cerebral  vesicles 
and  the  three  higher  sense-organs  (nose,  eye,  and  ear 
vesicle)  is  discernible  in  the  head ;  the  two  pairs  of  limbs 
can  be  traced  in  the  shape  of  four  simple  roundish 
unjointed  plates;  and  the  pointed  tail  sticks  out  at  the 
lower  part,  the  rudimentary  legacy  from  our  long-tailed 
ape-ancestors.  Although  the  cortex  is  not  yet  developed 
at  this  stage,  the  embryo  may  be  considered  to  have  a 
"soul"  {cf.  chapters  xiv.  and  xv.  of  my  AjitJiropogoiy, 
and  plates  8-14). 

It  is  said  to  be  a  great  merit  of  canon  law  that  it 
was  the  first  to  extend  legal  protection  to  the  human 
embryo,  and  punished  abortion  with  death  as  a  mortal 
sin.  But  as  this  mystical  theory  of  the  entrance  of  the 
soul  is  now  scientifically  untenable,  we  should  expect 
them  consistently  to  extend  this  protection  to  the  foetus 
in  its  earlier  stages,  if  not  to  the  ovum  itself.  The  ovary 
of  a  mature  maid  contains  about  70,000  ova;  each  of 
these  might  be  developed  into  a  human  being  under 
favorable  circumstances  if  it  united  with  a  male  sper- 
mium  after  its  release  from  the  ovary.  If  the  state  is 
so  eager  for  the  multiplication  of  its  citizens  in  the 
general  interest,  and  regards  prolific  reproduction  as  a 
"duty"   of   its   members,    this   is   certainly   a   "sin   of 

325 


THE    WONDERS    OF    LIFE 

omission.**  It  punishes  abortion  with  several  years' 
imprisonment.  But  while  civil  law  thus  takes  its  in- 
spiration from  canon  law,  it  overlooks  the  physiologi- 
cal fact  that  the  ovum  is  a  part  of  the  mother's  body 
over  which  she  has  full  right  of  control;  and  that  the 
embryo  that  develops  from  it,  as  well  as  the  new-born 
child,  is  quite  unconscious,  or  is  a  purely  "reflex  ma- 
chine," like  any  other  vertebrate.  There  is  no  mind  in 
it  as  yet ;  it  only  appears  after  the  first  year,  when  its 
organ,  the  phronema  in  the  cortex,  is  differentiated. 
This  interesting  fact  is  explained  by  the  biogenetic  law, 
which  shows  that  the  ontogeny  of  the  brain  is  a  con- 
densed recapitulation  of  its  phylogeny  in  virtue  of  the 
laws  of  heredity. 

The  biogenetic  law  applies  just  as  much  to  the  brain, 
the  organ  of  mind,  as  to  any  other  organ  of  the  human 
body.  On  the  strength  of  the  ontogenetic  facts,  which 
fall  under  direct  observation,  we  infer  that  there  was  a 
corresponding  development  in  the  phylogenetic  series  of 
our  animal  ancestors.  A  significant  confirmation  of  this 
inference  is  found  in  comparative  anatomy.  It  shows 
that  in  all  the  skull-animals  (craniota) — from  the  fishes 
and  amphibia  up  to  the  apes  and  man — the  brain  is 
developed  in  the  same  way,  as  a  vesicular  distension  of 
the  ectodermal  medullary  tube.  This  simple  oval  cere- 
bral vesicle  first  divides  into  three  and  afterwards  five 
successive  vesicles  by  transverse  constriction  (Anthro- 
pogeny,  chapter  xxiv.,  plate  24).  It  is  the  first  of  these 
vesicles,  the  cerebrum,  that  afterwards  becomes  the 
chemical  laboratory  of  the  mind.  In  the  lower  craniota 
(fishes  and  amphibia)  the  cerebrum  remains  very  small 
and  simple.  It  only  reaches  a  notably  higher  stage  in 
the  three  chief  classes  of  the  vertebrates,  the  amniotes. 
As  these  land-dwelling  and  air-breathing  craniota  have 
more  difficult  work  to  do  in  the  struggle  for  life  than 
their  lower  aquatic  ancestors,  we  find  much  more  varied 

326 


MENTAL    LIFE 

and  complex  habits  among  them.  These  hereditary 
habits  are  gradually  converted  into  instincts  by  func- 
tional adaptation  and  progressive  heredity;  and  with  the 
further  development  of  consciousness  in  the  higher 
mammals  we  have  at  last  the  appearance  of  reason. 
The  gradual  unfolding  of  the  mental  life  is  accompanied 
step  by  step  with  the  advance  of  its  anatomic  organ,  the 
phronema  in  the  cortex.  Recent  careful  investigations 
of  the  ontogeny  and  histology  of  the  origin  of  mi. id  (by 
Flechsig,  Hitzig,  Edinger,  Ziehen,  Oscar  Vogt,  etc.)  have 
given  us  an  interesting  insight  into  the  mysterious  proc- 
esses of  its  phylogeny. 

While  the  comparative  anatomy  of  the  cortex  gives  us 
a  good  idea  of  the  gradual  historical  development  of  the 
mind  in  the  higher  classes  of  vertebrates,  we  get  at  the 
same  time  from  their  fossilized  remains  positive  indica- 
tions as  to  the  period  of  time  in  which  this  phylogenesis 
has  slowly  taken  place.  The  historical  series  in  which 
the  classes  of  vertebrates  have  succeeded  each  other  in 
the  great  periods  of  the  organic  history  of  the  earth  is 
directly  demonstrated  by  their  fossil  remans — the  real 
commemorative  medals  of  natural  creation — and  gives 
us  a  most  valuable  record  of  the  ancestral  history  of  our 
race  and  of  the  mind.  The  oldest  strata  that  contain 
vertebrate  remains  form  the  huge  Silurian  System,  which 
were,  on  the  latest  calculations,  formed  more  than  a 
hundred  million  years  ago.  They  contain  a  few  fossil 
fishes.  In  the  succeeding  Devonian  System  these  are 
followed  by  the  dipneusta,  transitional  forms  between 
the  fishes  and  the  amphibia.  The  latter,  the  oldest  four- 
footed  and  five-toed  vertebrates,  appear  in  the  Carbo- 
niferous Period.  They  are  succeeded  in  the  Permian, 
the  next  system,  by  the  oldest  amniotes,  the  primitive 
reptiles  (tocosauria).  It  is  not  until  the  next  period  (the 
Triassic)  that  the  oldest  mammals  are  found,  small 
primitive  monotremes  (pantotJicria),  then  marsupials  in 

327 


THE    WONDERS    OF    LIFE 

the  Jurassic,  and  the  first  placentals  in  the  Cretaceans. 
The  great  wealth  of  varied  and  highly  organized  forms 
which  are  contained  in  this  third  and  last  sub-class  of 
the  mammals  appear  only  in  the  succeeding  Tertiary 
Period.  The  numbers  of  well-preserved  skulls  which 
these  placentals  have  left  behind  in  fossil  form  are 
particularly  important,  because  they  give  us  an  idea  of 
the  quantitative  and  qualitative  formation  of  the  brain 
within  the  various  orders;  thus,  for  instance,  in  the 
modern  carnivora  the  brain  is  from  two  to  four  times, 
and  in  the  modern  ungulates  from  six  to  eight  times,  as 
large  (in  proportion  to  the  size  of  the  body)  as  in  their 
earliest  Tertiary  ancestors.  It  is  also  found  that  the 
cortex  (the  real  organ  of  mind)  has  developed  in  the 
Tertiary  Period  at  the  expense  of  the  other  parts  of  the 
brain.  The  duration  of  this  Csenozoic  Period  has  lately 
been  calculated  at  three  million  years  (according  to  other 
geologists  twelve  to  fourteen  or  more  million  years). 
It  was,  at  all  events,  sufficient  to  make  possible  the 
gradual  development  of  the  human  mind  from  the  lower 
intelligence  of  our  ape-ancestors  and  the  instincts  of 
the  older  placentalia. 

We  have  given  the  physiological  name  of  the  "phro- 
nema,"  as  the  real  organ  of  mind  or  the  instrument  of 
reason,  to  that  part  of  the  cortex  on  the  normal  anatomic 
condition  of  which  the  action  of  the  human  mind 
depends.  The  remarkable  investigations  during  the 
last  few  decades  of  the  finer  texture  of  the  grey  cortex 
(or  cortical  substance  of  the  cerebrum)  have  shown 
that  its  structure — a  real  anatomic  "wonder  of  life" — 
represents  the  most  perfect  morphological  product  of 
plasm;  and  its  physiological  function  —  mind  —  is  the 
most  perfect  action  of  a  "dynamo-machine,"  the  highest 
achievement  that  we  know  anywhere  in  nature.  Millions 
of  psychic  cells  or  neurona — each  of  them  of  an  extremely 
elaborate  fibril  molecular  structure — are  associated  as 

328 


MENTAL    LIFE 

special  thought-organs  (phroneta)  at  certain  parts  of  the 
cortex,  and  these  again  are  built  up  into  a  large  har- 
monious system  of  wonderful  regularity  and  capacity. 
Each  phronetal  cell  is  a  small  chemical  laboratory,  con- 
tributing its  share  to  the  unified  central  function  of  the 
mind,  the  conscious  action  of  reason.  Scientists  are 
still  very  far  from  agreement  as  to  the  extent  of  the 
phronema  in  the  cortex  and  its  delimitation  from  the 
neighboring  sense-centres  (sensoria).  But  they  are  all 
agreed  that  there  is  such  a  central  organ  of  mind,  and 
that  its  normal  anatomic  and  chemical  condition  is  the 
first  requisite  for  the  life  of  the  human  mind.  This 
behef — one  of  the  foundations  of  monistic  psychology — 
is  confirmed  by  the  study  of  psychiatry. 

The  study  of  the  diseased  organism  has  greatly 
furthered  our  knowledge  of  the  normal  frame.  Diseases 
are  so  many  physiological  experiments  made  by  nature 
herself  under  special  conditions,  which  experimental 
physiology  would  often  be  unable  to  arrange  artificially. 
The  thoughtful  physician  or  pathologist  can  often  obtain 
most  important  knowledge  of  the  function  of  organs  by 
carefully  observing  them  during  disease.  This  is  espe- 
cially true  of  diseases  of  the  mind,  which  always  have  their 
immediate  foundation  in  an  anatomical  or  chemical 
modification  of  certain  parts  of  the  brain.  Our  advanc- 
ing knowledge  of  the  localization  of  mental  functions,  or 
of  their  connection  with  special  phroneta  or  organs  of 
thought,  is  for  the  most  part  based  on  the  experience 
that  the  destruction  of  the  one  is  followed  by  the  extinc- 
tion of  the  other.  Modern  psychiatry,  the  empirical 
science  of  mental  disease,  has  thus  become  an  important 
element  of  our  monistic  psychology.  If  Immanuel  Kant 
had  studied  it  and  had  visited  the  asylum  wards  for  a 
few  months,  he  would  certainly  have  escaped  the  duaHst 
errors  of  his  philosophy.  We  may  say  the  same  of  the 
modern  metaphysical  psychologists  who  built  up  a  mystic 

329 


THE    WONDERS    OF    LIFE 

theory  of  an  immortal  soul  without  knowing  the  anat- 
omy, physiology,  and  pathology  of  the  brain. 

The  comparative  anatomy,  physiology,  and  pathology 
of  the  brain,  in  concurrence  with  the  results  of  ontogeny 
and  phylogeny,  have  led  us  to  form  the  sound  monistic 
principle  that  the  human  mind  is  a  function  of  the 
phronema,  and  that  the  neurona  of  the  latter,  or  the 
phronetal  cells,  are  the  real  elementary  organs  of  mental 
life.  Hence  modern  energism  is  perfectly  justified  in 
regarding  mental  energy  (in  all  its  forms)  from  the  same 
point  of  view  as  all  other  forms  of  nervous  energy,  and  in 
fact  all  manifestations  of  energy  in  organic  or  inorganic 
nature.  Fechner's  psychophysics  had  already  shown 
that  a  part  of  this  nervous  energy  s  measurable  and 
methematically  reducible  to  the  mechanical  laws  of 
physics  {Riddle,  chapter  vi.)  Ostwald  has,  in  his  Natural 
Philosophy,  lately  emphasized  the  fact  that  all  the  mani- 
festations of  mental  life,  not  only  sensation  and  will,  but 
even  thought  and  consciousness,  can  be  reduced  to 
nervous  energy.  Hence  we  may  distinguish  what  are 
called  mental  forces  from  the  other  expressions  of 
nervous  energy  as  phronetic  energy.  The  monistic  re- 
search of  Ostwald  on  the  energy -processes  in  mental  life 
(chapter  xviii.),  consciousness  (chapter  xix.),  and  will 
(chapter  xx.)  is  very  notable,  and  confirms  the  views  I 
advanced  in  the  second  part  of  the  Riddle  (chapters  vi., 
x.,  and  xi.).  Ostwald  has,  however,  caused  some  mis- 
understanding by  insisting  on  substituting  his  idea  of 
energy  for  the  pure  notion  of  substance  (as  Spinoza 
had  formulated  it),  and  by  rejecting  the  other  attribute 
of  substance,  matter.  His  supposed  "Refutation  of 
Materialism"  is  a  mere  attack  on  windmills;  his  ener- 
gism (the  consistent  dynamism  of  Leibnitz,  etc.)  is  just 
as  one-sided  as  its  apparent  opposite,  the  consistent 
materialism  of  Democritus,  Holbach,  etc.  The  latter 
makes  matter  precede  force ;  the  former  regards  matter  as 

330 


MENTAL    LIFE 

the  product  of  force.  Monism  escapes  the  one-sidedness 
of  both  systems,  and,  as  hylozoism,  refuses  to  separate 
the  two  attributes  of  substance,  space-filhng  matter  and 
active  energy.  This  appHes  to  mental  hfe  just  as  to  any 
other  natural  process;  our  mental  forces  or  phronetic 
energies  are  just  as  much  bound  up  with  the  neuroplasm, 
the  living  plasm  of  the  neurona  in  the  cortex,  as  the 
mechanical  energy  of  our  muscles  is  with  the  contractile 
myoplasm,  the  living  muscular  substance.  


In  the  exhaustive  study  of  consciousness  which  I  gave 
in  the  tenth  chapter  of  the  Riddle  I  sought  to  show  that 
this  enigmatic  function — the  central  mystery  of  psychol- 
ogy—  is  not  a  transcendental  problem,  but  a  natural 
phenomenon,  subject  to  the  law  of  substance,  as  much  as 
any  other  psychic  power.  The  child's  consciousness  only 
develops  long  after  its  first  year,  and  grows  as  gradually 
as  any  other  psychic  function;  like  these,  it  is  bound  up 
with  the  normal  anatomic  and  chemical  condition  of  its 
organs,  the  phroneta  in  the  cortex.  Consciousness 
develops  originally  out  of  unconscious  functions  (as 
an  "inner  view,"  or  mirroring,  of  the  action  of  the 
phronema) ;  and  at  any  time  an  unconscious  process  in 
the  cortex  may  come  within  the  sphere  of  consciousness 
by  having  the  attention  directed  to  it.  On  the  other 
hand,  conscious  actions,  which  need  a  good  deal  of 
attention  when  they  are  first  learned  (such  as  playing 
the  piano),  may  become  unconscious  through  frequent 
repetition  and  practice.  The  fact  that  chemical  energy 
is  converted  in  the  phronetal  cells  during  any  of  these 
actions  is  proved  by  the  fatigue  and  exhaustion  which 
prolonged  mental  work  causes  in  the  brain,  just  as 
mechanical  work  does  in  the  muscles.  Fresh  matter  has 
to  be  supplied  by  the  food  before  the  mental  work  can 
be  continued.  Moreover,  it  is  well  known  that  various 
drinks  have  a  considerable  influence  on  consciousness 
(coffee   and   tea,   beer  and   wine) ;  and   the   temporary 

331 


J 


THE    WONDERS    OF    LIFE 

extinction  of  it  under  chloroform  or  ether  is  an  analo- 
gous fact.  Again,  the  familiar  phenomena  of  the  dream, 
the  deviations  from  normal  consciousness,  hallucinations, 
delusions,  etc.,  must  convince  every  impartial  thinker 
that  these  mental  functions  are  not  of  a  metaphysical 
character,  but  physical  processes  in  the  neuroplasm  of 
the  brain,  and  thoroughly  dependent  on  the  law  of 
substance. 

In  complete  contrast  to  this  natural  monistic  con- 
ception of  the  human  mind,  which  is,  in  my  opinion, 
definitely  established  by  nineteenth-century  science,  we 
have  the  older  dualistic  estimate  of  it  which  is  still  wide- 
ly accepted  both  by  unlearned  and  learned,  especially 
metaphysicians  and  theologians.  I  have  already  dealt 
in  the  Riddle  (chapter  xi.)  with  the  grounds  for  this  be- 
lief in  an  immaterial  soul,  and  expressed  my  conviction 
that  "the  belief  in  the  immortality  of  the  human  soul 
is  in  flagrant  contradiction  to  the  soundest  empirical 
principles  of  modern  science."  I  must  refer  the  reader 
to  what  I  said  there  about  thanatism  and  athanatism, 
only  reminding  him  once  more  of  the  immense  influence 
of  the  Kantist  philosophy  in  maintaining  this  belief  in 
the  spirituality  of  the  soul.  Kant  derived  from  the 
introspective  study  of  his  own  gifted  mind  an  extremely 
high  estimate  of  human  reason,  and  he  fallaciously  trans- 
ferred this  estimate  to  the  human  mind  generally.  He 
did  not  perceive  that  it  is  either  wholl}^  wanting  in  the 
savage,  or  does  not  rise  much  above  the  stage  which  has 
been  reached  by  the  intelligence  of  the  dog,  horse,  ele- 
phant, and  other  advanced  animals. 

Modern  anthropogeny  has  raised  the  theory  of  evolu- 
tion to  the  rank  of  an  historical  fact.  All  the  various 
organs  of  our  body  resemble  those  of  our  nearest  rela- 
tives, the  anthropoid  apes,  in  their  structure  and  com- 
position. They  only  differ  from  them  in  details  of  form 
and  size,  which  are  determined  by  inherited  variations 

332 


MENTAL    LIFE 

of  growth.  But  the  functions  as  well  as  the  organs 
have  been  inherited  by  man  from  his  primate  ancestors. 
This  appUes  to  the  mind  also,  which  is  merely  the  col- 
lective function  of  the  phronema,  the  central  organ  of 
thought.  An  impartial  comparison  of  mental  life  in  the 
anthropoid  ape  and  the  savage  shows  that  the  differ- 
ences between  the  two  are  not  more  considerable  than 
the  differences  in  the  structure  of  their  brains.  Hence, 
if  one  accepts  the  dualistic  theory  of  the  soul  formulated 
by  Plato  and  Kant  and  accepted  by  so  many  modern 
psychologists,  it  is  necessary  to  attribute  an  immortal 
soul  to  the  anthropoid  apes  and  the  higher  mammals 
(especially  to  domestic  dogs)  just  as  well  as  to  savage 
or  civilized  man  (cf.  chapter  xi.  of  the  Riddle). 

The  thorough  and  careful  study  of  the  mental  life  of 
the  savage,  supported  by  the  results  of  anthropogeny 
and  ethnography,  has  in  the  course  of  the  last  forty 
years  decided  the  issue  of  this  struggle  between  the 
conflicting  theories  of  the  origin  of  civilization.  The 
older  theory  of  degeneration,  based  on  religious  beliefs, 
and  so  preferred  by  theologians  and  theosophists,  de- 
clared that  man — the  "image  of  God" — was  created 
originally  with  perfect  bodily  and  mental  powers,  and 
only  fell  away  from  his  high  estate  after  the  original  sin. 
On  this  view  the  present  savages  are  degenerate  descend- 
ants of  the  first  godlike  men.  (In  tropical  lands  the 
anthropoid  apes  are  in  similar  fashion  regarded  by  the 
natives  as  degenerate  branches  of  their  own  stem!) 
Although  this  Bil^lical  degeneration  theory  is  still  taught 
in  most  of  our  schools,  and  even  supported  by  a  few 
mystic  ])hilosophers,  it  had  lost  all  scientific  counte- 
nance before  the  end  of  the  nineteenth  century.  It  is 
now  replaced  by  the  modern  theory  of  evolution,  whit  h 
was  represented  by  Lamarck,  Goethe,  and  Herder  a 
century  ago,  and  raised  to  a  ]ircdominant  position  in 
ethnography  by  Darwin  and  Lubbock.     It  has  taught 

333 


THE    WONDERS    OF    LIFE 

us  that  human  civilization  is  the  outcome  of  a  long  and 
gradual  process  of  evolution,  covering  thousands  of 
years.  The  civilized  races  of  our  time  have  arisen  from 
less  civilized  races,  and  these  in  turn  from  lower,  until 
we  reach  the  savage  races  which  show  no  trace  of  civ- 
ilization. 

Ethnologists  distinguish  as  a  separate  class  the  races 
which  are  found  midway  between  the  civilized  peoples 
and  the  savages.  We  shall  deal  with  their  classification 
and  characteristics  later  on  (chapter  xvii.).  These  races 
show  some  advance  on  the  artistic  instinct  which  we 
find  in  a  slight  degree  even  among  the  savages  at  times ; 
moreover,  their  animal  curiosity  develops  into  human 
curiosity,  and  raises  the  question  of  the  causes  of  phe- 
nomena, the  germ  of  all  science. 

Civilized  races,  which  occupy  the  next  stage  to  these, 
are  raised  above  them  by  the  formation  of  larger  states 
and  a  greater  division  of  labor.  The  specialization  of 
the  various  groups  of  workers  and  the  greater  ease  of 
maintenance  permit  a  further  development  of  art  and 
science.  To  these  groups  belong,  of  living  races,  the 
majority  of  the  Mongolians,  and  the  greater  part  of  the 
inhabitants  of  Europe  and  Asia  in  ancient  and  mediaeval 
times.  The  great  ancient  civilizations  of  China,  South- 
em  India,  Asia  Minor,  Egypt,  and  afterwards  of  Greece 
and  Italy,  show  not  only  a  great  development  of  art  and 
science,  but  also  a  concern  for  legislation,  religious  wor- 
ship, education  of  the  young,  and  the  spread  of  knowl- 
edge by  written  books. 

Civilization  in  the  narrower  sense,  characterized  by  a 
high  development  of  art  and  science  and  the  manifold 
application  of  them  to  practical  life  in  legislation,  educa- 
tion, etc.,  was  greatly  advanced  even  in  antiquity  among 
several  nations — in  Asia  by  the  Chinese,  Southern  Ind- 
ians, Babylonians,  and  Egyptians;  in  Europe  by  the 
Greeks  and  Romans  of  the  classic  age.     However,  their 

334 


MENTAL    LIFE 

results  were  at  first  restricted  to  narrow  fields,  and  were 
mostly  lost  during  the  Middle  Ages.  Modem  civiliza- 
tion rose  to  importance  about  the  end  of  the  fifteenth 
century,  when  the  invention  of  printing  had  made  pos- 
sible the  spread  of  knowledge  far  and  wide,  the  dis- 
covery of  America  and  circumnavigation  of  the  globe 
had  widened  the  horizon,  and  the  Copemican  system 
had  demolished  the  error  of  geocentricism.  Then  began 
the  many-sided  growth  of  civilization  which  has  reached 
so  marvellous  a  height  in  the  nineteenth  century  through 
the  extraordinary  development  of  science.  Then  at 
last  free  reason  could  triumph  over  the  prevailing  me- 
diaeval superstition. 


\ 


XV 

THE  ORIGIN  OF  LIFE 

The  miracle  of  the  origin  of  hfe — Creation  of  species:  Moses  and 
Agassiz — Creation  of  the  first  cells:  Wigand  and  Reinke — 
Agnostic  position :  resignation — Eternity  hypothesis  (dual- 
istic,  Helmholtz;  monistic,  Preyer) — Archigony  hypothesis 
(autogony  hypothesis,  Haeckel,  Nageli;  cyanic  hypothesis, 
Pfliiger,  Verworn) — Spontaneous  generation — Saprobiosis 
or  necrobiosis — Experiments  in  spontaneous  generation — 
Pasteur — Stages  of  archigony — Observation  of  archigony — 
Synthesis  of  plasma — Value  of  the  unsuccessful  experi- 
ments to  produce  plasm  artificially — The  logic  of  modern 
experimental  biology. 

THE  question  of  the  origin  of  life  is  one  of  the  most 
important  and  interesting,  but  one  of  the  most  dif- 
ficult and  complicated,  problems  with  which  the  mind 
of  man  has  been  occupied  for  thousands  of  years.  There 
are  few  other  questions  (such  as  the  freedom  of  the  will  or 
personal  immortality)  on  which  such  different  and  con- 
tradictory views  have  been  expressed,  and  few  that 
remain  so  far  from  being  closed  at  the  present  day. 
There  are,  moreover,  few  problems  on  which  the  opinions 
of  even  distinguished  thinkers  diverge  so  much,  and  have 
degenerated  so  much  into  fantastic  hypotheses.  This  is 
partly  due  to  the  extreme  difficulty  of  giving  a  strictly 
scientific  solution  of  the  problem  and  partly  to  the  con- 
fusion of  ideas  which  is  so  great  in  this  controversy,  the 
lack  of  clear  rational  insight,  and  the  powerful  authority 
of  the  prevailing  religious  faith  and  other  venerable 
dogmas. 

33^ 


THE    ORIGIN    OF    LIFE 

The  easiest  and  quickest  thin^^  to  do  is  to  cut  the 
Gordian  knot  of  the  question  with  the  sword  of  faith,  or 
answer  it  with  a  behef  in  a  supernatural  creation.  The 
first  article  of  the  creed  was  given  to  us  in  childhood  as 
the  foundation  of  all  cosmic  philosophy.  It  is  based  on 
the  Mosaic  account  of  creation  in  the  first  chapter  of 
Genesis.  As  I  have  fully  examined  its  scientific  value  in 
the  second  chapter  of  my  History  of  Creation,  I  may  refer 
the  reader  thereto.  It  is  unquestionable  that  this  myth 
still  has  a  very  great  practical  influence;  the  great 
majority  of  the  clergy  cling  to  it  because  it  is  found  in 
the  infallible  ' '  word  of  God. ' '  Most  governments,  which 
hold  blind  faith  to  be  an  important  element  of  education, 
include  it  in  the  code  for  the  elementary  school.  On  the 
other  hand,  it  is  difficult  to  find  a  man  of  science  who 
will  uphold  it  to-day.  The  gifted  Louis  Agassiz  made 
one  of  the  most  remarkable  attempts  to  do  this  in  his 
Essay  on  Classification  (1858),  a  book  that  appeared 
almost  contemporaneously  with  Darwin's  epoch-making 
Origin  of  Species,  and  dealt  with  the  general  problems  of 
biology  from  the  directly  opposite,  the  mystic,  point  of 
view.  According  to  Agassiz,  each  species  of  animal  or 
plant  is  an  "incarnate  thought  of  the  Creator." 

Differing  from  this  Biblical  fancy  of  the  supernatural 
creation  of  each  species,  two  botanists,  Wigand  of 
Marburg  and  Reinke  of  Kiel,  have  lately  restricted  the 
action  of  the  celestial  architect  very  considerably;  they 
have  ascribed  to  him  only  the  creation  of  the  primitive 
cells,  which  he  is  supposed  to  have  endowed  with  the 
power  to  develop  into  the  higher  organisms.  Wigand 
assumed  for  the  origin  of  each  species  a  special  primitive 
cell  and  a  long  phylogenetic  develo])ment  of  this;  Reinke 
prefers  a  stem,  composed  of  a  number  of  species.  These 
modern  creative  theories  have  no  more  scientific  value 
than  that  of  Agassiz;  they  are  equally  based  on  pure 
superstition  {cf.  chapters  i.-iii.). 

337 


THE    WONDERS    OF    LIFE 

A  different  attitude  from  this  irrational  positive  super- 
stition is  the  sceptical  view  of  those  scientists  who 
regard  the  question  of  the  origin  of  Hfe  as  insoluble  or 
transcendental.  Darwin  and  Virchow  are  representa- 
tives of  this  agnostic  position;  they  held  that  we  know 
nothing,  and  can  know  nothing,  about  the  origin  of  the 
first  organisms.  Darwin,  for  instance,  explains  in  his 
chief  work  that  he  "has  nothing  to  do  with  the  origin  of 
the  fundamental  spiritual  forces,  or  with  that  of  life 
itself."  This  is  a  complete  abandonment  of  the  task  of 
solving  a  scientific  problem  which  must  present  as  def- 
inite a  subject  of  inquiry  to  modern  research  as  any 
other  evolutionary  problem.  The  origin  of  life  on  our 
planet  represents  a  fixed  point  in  its  history.  However, 
there  is  nothing  to  be  said  if  a  scientist  chooses  to  make 
no  inquiry  into  it.  A  number  of  distinguished  modern 
scientists  maintain  this  agnostic  attitude ;  they  are  more 
or  less  convinced  that  the  origin  of  life  is  a  natural  process, 
but  believe  we  have  not  as  yet  the  means  to  explain  it. 

Different,  again,  is  a  third  attitude  which  regards  the 
problem  of  the  origin  of  life  as  extremely  difficult,  yet 
capable  of  solution.  This  is  the  position  of  Dubois- 
Reymond,  for  instance,  who  counts  the  origin  of  hfe 
as  the  third  great  cosmic  problem.  Most  of  the  modern 
scientists  who  have  worked  on  the  problem  are  of  this 
opinion,  although  their  views  as  to  the  way  of  solving  it 
differ  very  much.  We  are  confronted,  in  the  first  place, 
with  two  essentially  different  views  which  we  may  call 
the  eternity-hypothesis  and  the  theory  of  archigony 
(or  spontaneous  generation).  According  to  the  first 
view,  organic  life  is  eternal;  according  to  the  second, 
it  began  at  a  definite  point  of  time.  The  eternity- 
hypothesis  has  assumed  two  very  different  forms,  one 
of  which  has  a  dualistic  and  the  other  a  monistic  base. 
Helmholtz  is  a  representative  of  the  former  theory,  and 
Preyer  of  the  latter. 

33^ 


THE    ORIGIN    n  V    L  I  F  E 

Hermann  Eberhard  Richter  put  forward,  in  1865,  the 
hypothesis  that  infinite  space  is  full  throughout  of  the 
germs  of  living  things,  just  as  it  is  of  inorganic  bodies; 
both  of  them  are  in  a  condition  of  eternal  development. 
When  the  ubiquitous  germs  reach  a  mature  and  habita- 
ble cosmic  body,  which  possesses  heat  and  moisture  in 
the  proper  degrees  for  their  development,  they  break 
into  life,  and  may  lead  to  the  formation  of  a  whole  world 
of  living  things.  Richter  conceives  these  ubiquitous 
germs  as  living  cells,  and  formulates  the  princii)le: 
Omne  vivuni  ab  cutcruitate  e  cellida  (Every  living  thing  is 
eternal  and  from  a  cell).  In  much  the  same  way  the 
botanist  Anton  Kerner  postulates  the  eternity  of  organic 
life  and  its  complete  independence  of  the  inorganic 
world.  But  the  difficulties  encountered  by  this  hypoth- 
esis, in  the  indefinite  form  that  Kerner  gives  it,  are  so 
great  and  so  obvious  that  his  theory  has  won  no  rec- 
ognition. 

However,  the  "cosmozoic  hypothesis"  attained  a 
great  popularity  when  it  was  afterwards  taken  up  by  two 
of  the  most  distinguished  physicists,  Hermann  Helm- 
holtz  and  Sir  W.  Thomson  (Lord  Kelvin).  Helmholtz 
formulated  the  alternative  thus  (in  1884)*:  "Organic  life 
either  came  into  existence  at  a  certain  period,  or  it  is 
eternal. ' '  He  declared  for  the  latter  view,  on  the  ground 
that  we  have  not  succeeded  in  producing  living  organisms 
by  artificial  means.  He  supposes  that  the  meteors  that 
roam  about  the  universe  might  contain  the  germs  of 
organisms,  and,  under  favorable  conditions,  these  might 
reach  the  earth  or  other  planets  and  develop  thereon. 
This  cosmozoic  hypothesis  of  Helmholtz  is  untenable, 
because  the  physical  features  of  space  (the  extreme 
temperatures,  the  absolute  dryness,  the  absence  of  atmos- 
phere, etc.)  exclude  the  lasting  existence  of  plasm  on 
meteorites  in  the  form  of  organic  germs  with  a  capacity 
to  Uve.     The  hypothesis  is,  moreover,  logically  useless, 

339 


THE    WONDERS    OF    LIFE 

since  it  does  not  solve,  but  postpones,  the  question  of  the 
origin  of  organic  life.  If  it  is  consistently  worked  out, 
it  leads  to  pure  cosmological  dualism. 

Another  and  very  different  theory  of  the  eternity  of 
life  has  been  elaborated  by  Theodor  Fechner  (1873)  and 
Wilhelm  Preyer  (1880).  Both  these  scientists  extend 
the  idea  of  life  to  the  whole  cosmos,  and  reject  the  dis- 
tinction that  is  usually  drawn  between  the  organic  and 
the  inorganic.  Fechner  goes  so  far  as  to  ascribe  con- 
sciousness to  the  whole  universe  and  every  single  body 
in  it,  and  regards  individual  organisms  merely  as  parts 
of  one  vast  universal  organism.  His  system  is,  there- 
fore, panpsychistic,  and,  at  the  same  time,  pantheistic, 
as  he  somewhat  mystically  connects  the  idea  of  a  con- 
scious God  with  that  of  a  living  universe.  Preyer 
generally  agrees  with  him  in  extending  the  idea  of  life 
to  the  whole  universe,  and  conceiving  it  as  an  organism. 
He  applies  his  theory  in  the  symbolic  sense  which  I 
alluded  to  on  page  38,  and  described  as  impracticable. 
The  fiery  mass  of  the  forming  earth  is  the  gigantic 
organism,  and  Preyer  gives  the  name  of  "life"  to  its 
rotatory  movement  (or  gravitational  energy).  As  it 
cooled  down,  the  heavier  metals  (the  dead  inorganic 
masses)  separated  from  it;  from  the  rest  of  it  were 
formed  first  simple  and  afterwards  complex  carbon-com- 
binations, and  finally  albumin  and  plasm.  This  extension 
of  the  word  "organism  "  has  very  properly  met  with  little 
approval  in  biology.  It  only  increases  the  confusion, 
and  the  difficulty  of  marking  off  biological  from  abio- 
logical  science,  which  is  both  practically  necessary  and 
theoretically  justified. 

If,  then,  in  our  opinion,  the  eternity -hypotheses  are  of 
no  more  value  than  the  creation-hypotheses,  we  have 
left,  for  the  purpose  of  answering  the  great  question  of 
the  origin  of  life,  only  the  third  group  of  scientific 
theories  which  I  have  combined  under  the  general  head 

340 


THE    ORIGIN    OF    LIFE 

of  archigony.  They  start  from  the  following  points: 
I.  Organic  life  is  everywhere  bound  up  with  the  plasm  ^ 
(or  protoplasm) ,  a  chemical  substance  of  a  viscous  char- 
acter, having  albuminous  matter  and  water  as  its  chief 
constituents.  2.  The  characteristic  movements  of  this 
living  substance,  to  which  we  give  the  name  of  organic 
life,  are  physical  and  chemical  processes,  that  can  only 
take  place  within  certain  limits  of  temperature  (between 
the  freezing-point  and  boiling-point  of  water).  3.  Be- 
yond these  limits  organic  life  may  in  certain  circum- 
stances be  maintained  for  a  time  in  a  latent  condition 
(apparent  death,  potential  life) ;  but  this  latent  condi- 
tion is  restricted  to  a  certain  (and  generally  short)  peri- 
od. 4.  As  the  earth,  like  all  the  other  planets,  was  for 
a  long  time  in  a  state  of  incandescence,  at  a  temperature 
of  several  thousand  degrees,  living  organisms  (viscous 
albuminoids)  cannot  possibly  have  existed  on  it,  and  so 
cannot  be  eternal.  5.  Fluid  water,  the  first  condition 
for  the  appearance  of  organic  life,  cannot  have  formed 
on  it  until  the  crust  at  the  surface  had  fallen  below  boil- 
ing-point. 6.  The  chemical  processes  which  first  set  in 
at  this  stage  of  development  must  have  been  catalyses, 
which  led  to  the  formation  of  albuminous  combinations, 
and  eventually  of  plasm.  7.  The  earliest  organisms  to 
be  thus  formed  can  only  have  been  plasmodomous  mo- 
nera,  structureless  organisms  without  organs;  the  first 
forms  in  which  the  living  matter  individualized  were 
probably  homogeneous  globules  of  plasm,  like  certain  of 
the  actual  chromacea  (chroococcus).  8.  The  first  cells 
were  developed  secondarily  from  these  primitive  monera, 
by  separation  of  the  central  caryoplasm  (nucleus)  and 
peripheral  cytoplasm  (cell-body). 

The  monistic  hypothesis  of  abiogenesis,  or  autogony 
(  =  self- development)  in  the  strictly  scientific  sense  of 
the  word,  was  first  formulated  by  me  in  1866  in  the 
second    book    of    the   General   Morphology.     The    solid 

341 


THE    WONDERS    OF    LIFE 

foundation  for  it  was  found  in  the  monera  I  had  de- 
scribed, the  very  simple  organisms  without  organs  that 
had  up  to  that  time  been  overlooked  or  thrust  aside. 
It  is  of  radical  importance,  in  giving  a  naturalistic 
solution  of  the  problem  of  the  origin  of  life,  to  start  from 
these  structureless  granules  of  living  matter,  and  not — 
as  still  generally  happens — from  the  cell ;  these  nucleated 
elementary  organisms  could  not  be  the  earliest  archigo- 
nous  living  things,  but  must  have  been  evolved  second- 
arily from  the  unnucleated  monera.  Hence,  I  made  a 
very  thorough  study  of  these  rudimentary  organisms  in 
my  Monograph  on  the  Monera  (1870),  and  endeavored  to 
formulate  it  more  clearly  later  on  (in  the  first  volume  of 
the  Systematic  Phytogeny).  In  regard  to  the  chemical 
question  of  the  first  formation  of  plasm  and  its  inorganic 
preparation,  Edward  Pfliiger  conducted  some  valuable 
investigations,  and  recognized  that  the  radical  of  cyano- 
gen was  the  chief  element  of  the  living  plasm.  I  may 
therefore  distinguish  two  different  stages  of  the  theory 
— my  own  older  autogony-hypothesis  and  the  later 
cyanogen-hypothesis. 

The  theory  of  abiogenesis,  or  archigony,  which  I 
advanced  in  1866,  and  have  developed  in  later  writings, 
appeals  directly  to  the  biochemical  facts  that  modern 
vegetal  physiology  has  firmly  established.  The  chief  of 
these  facts  is  that  even  the  living  green  plant-cell  has  the 
synthetic  faculty  of  plasmodomism  or  carbon-assimila- 
tion; that  is  to  say,  it  is  able  to  build  up,  by  a  chemical 
synthesis  and  reduction,  from  simple  inorganic  com- 
pounds (water,  carbonic  acid,  nitric  acid,  and  ammonia), 
the  complex  albuminous  compounds  which  we  call 
plasm  or  protoplasm,  and  which  we  regard  as  the  active 
living  substance  and  the  true  material  basis  of  all  vital 
function  (cf,  chapter  vi.).  All  botanists  are  now  agreed 
that  this  most  important  process  of  vegetal  life,  the 
fundamental  process  of  all  organic  life  and  all  organiza- 

342 


THE    ORIGIN     OF    LIFE 

tion,  is  a  purely  chemical  (or,  in  the  wider  sense,  physi- 
cal) process,  and  that  there  is  no  question  of  a  specific 
vital  force  or  a  mystic  constructor  (like  the  famous 
"mechanical  engineer  of  life"),  or  any  other  tran- 
scendental agency,  in  connection  with  it.  The  tiny 
chemical  laboratory  in  which  this  remarkable  organo- 
plastic  process  takes  place  under  the  influence  of  sun- 
light is,  in  the  simplest  plants,  the  chromacea,  either 
the  whole  homogeneous  globule  of  plasm  {chroococcus) 
or  its  bluish-green  surface-layer,  which  is  active  as  a 
chromatic  principle  (chromatophore).  But  in  most 
plants  these  reduction-laboratories  are  the  chromatella 
or  chromatophora,  which  have  been  differentiated  from 
the  rest  of  the  plasm  of  the  cell,  and  are  colorless  globu- 
lar leucoplasts  within  its  dark  interior,  or  green  chromo- 
plasts  (or  granules  of  chlorophyll)  at  its  illumined  sur- 
face. My  theory  of  archigony  only  assumes  that  this 
chemical  process  of  plasmodomism  which  we  find  re- 
peated every  second  in  every  plant-cell  exposed  to  the 
sunlight,  and  which  has  become  an  "inherited  habit" 
of  the  green  plant  -  cell,  developed  of  itself  at  the  be- 
ginning of  organic  life;  in  other  words,  it  is  a  catalytic 
process  (or  one  analogous  to  catalysis),  the  physical 
and  chemical  conditions  of  which  were  present  in  the 
condition  of  organic  nature  at  that  time. 

My  hypothesis  was  very  strongly  confimied  twenty 
years  ago  by  the  adhesion  of  the  able  botanist,  Carl 
Niigeli.  In  his  instructive  work,  A  Mechanical- physio- 
logical Theory  of  Evolution  (1884),  he  supported  all  the 
principal  ideas  as  to  the  natural  origin  of  life  which  1  had 
advanced  in  1866.  He  formulates  the  chief  part  of 
them  in  this  admirable  principle: 

The  origin  of  the  organic  from  the  inorganic  is.  in  the  first 
place,  not  a  question  of  experience  and  experiment,  but  a  fact 
deduced  from  the  law  of  the  constancy  of  matter  and  force. 
If  all  things  in  the  material  world  are  causally  related,  if  all 

343 


THE    WONDERS    OF    LIFE 

phenomena  proceed  on  natural  principles,  organisms,  which 
are  formed  of  and  decay  into  the  same  matter,  must  have  been 
derived  originally  from  inorganic  compounds. 

This  excellent  and  clear  declaration  of  a  distinguished 
scientist  and  profound  thinker  might  be  taken  to  heart 
by  the  "exact"  scientists  who  are  always  attacking  the 
monistic  theory  of  archigony  as  an  unproved  hypothesis, 
or  regard  the  whole  problem  as  insoluble.  Nageli  has, 
moreover,  proceeded  to  make  a  thorough  study  of  the 
molecular  processes  involved,  and  embodied  the  results 
in  his  idioplasm  theory.  He  believes  that  at  the  be- 
ginning of  organization  the  definite  autonomous  ar- 
rangement of  the  smallest  homogeneous  parts  of  the 
plasm  was  a  matter  of  the  greatest  importance.  In  his 
opinion  these  "micella"  are  crystalline  groups  of  mole- 
cules, arranged  multifariously  in  strings  and  parallel 
rows. 

A  similar  and  more  elaborate  attempt  to  give  a  physi- 
cal explanation  of  the  processes  of  archigony  and  trace 
them  to  mechanical  molecular  structures  was  made  by 
Ludwig  Zehnder  in  1899  in  his  work  on  The  Origin  of 
Life.  He  believes  that  the  smallest  and  lowest  life- 
unities  (the  micellar  strings  of  Nageli  and  the  biophora 
of  Weismann,  corresponding  to  my  plastidules)  have  a 
tubular  shape,  and  so  he  calls  them  "fistella."  He  sup- 
poses that  these  invisible  molecular  structures  are  regu- 
larly arranged  in  millions  in  the  plasma  of  the  cell,  and 
differentiated  in  such  a  way  that  some  will  effect  endos- 
mosis,  others  contraction,  others  the  conduction  of  stim- 
uli, and  so  on.  As  in  the  similar  work  of  Nageli  and 
others,  the  value  of  this  molecular  hypothesis  is  that  it 
stimulates  us  to  attempt  to  conceive  the  mode  of  the 
arrangement  and  movement  of  the  molecules  of  plasm 
in  the  process  of  archigony  on  physical  principles. 

A  more  interesting  and  notable  attempt  to  penetrate 
into  the  mysterious  obscurity  of  the  chemical  processes 

344 


THE    ORIGIN    01'     LIFE 

in  archigony  was  made  in  1875  by  the  distinguished 
physiologist,  Edward  Pfliiger,  in  his  essay  on  Physio- 
logical Combustion  in  the  Living  Organism.  He  starts 
from  the  fact  that  the  plasm  (or  protoplasm)  is  the 
material  basis  of  all  vital  phenomena,  and  that  this 
living  matter  owes  its  properties  to  the  chemical  prop- 
erties of  the  albumin  (whether  we  regard  this  as  a 
chemical  unity,  protein  or  protalbumin,  or  as  a  mixture 
of  different  compounds).  However,  Pfliiger  sharply 
distinguishes  between  the  living  albumin  of  the  plasm 
out  of  which  all  organisms  are  built,  and  the  dead 
albumin,  such  as  we  find  it,  for  instance,  in  the  glairy 
albumin  of  the  hen's  e^gg.  Only  the  living  albumin 
(plasm)  decomposes  of  itself  in  a  slight  degree,  and  to 
a  greater  extent  under  the  influence  of  external  exci- 
tation; the  dead  albumin  will  remain  intact  for  a  long 
time  under  favorable  conditions.  The  cause  of  the 
extraordinary  instability  of  the  living  albumin  is  its 
intramolecular  oxygen — that  is  to  say,  the  oxygen  that 
is  taken  into  the  interior  of  the  plasma-molecules  in 
breathing,  and  effects  there  a  disassociation,  surround- 
ing the  atoms  and  breaking  up  the  new-formed  groups. 
The  real  cause  of  this  rapid  decomposability  of  the 
plasm,  and  of  the  accompanying  fonnation  of  carbonic 
acid,  is  found  in  the  cyanogen,  a  remarkable  body  com- 
posed of  an  atom  of  carbon  and  an  atom  of  nitrogen, 
which,  in  conjunction  with  potassium,  forms  the  well- 
known  and  very  virulent  poison,  cyanide  of  potassium. 
The  non-nitrogenous  decomposition-products  of  the  dead 
and  the  living  albumin  agree  in  the  main,  but  their 
nitrogenous  products  are  totally  different.  Uric  acid, 
creotin,  guanine,  and  the  other  decomposition  products 
of  plasm  contain  the  cyanogen-radical,  and  the  most 
important  of  all,  urea,  can  be  artificially  produced  from 
cyanic  compounds,  as  Wohler  showed  in  1828.  From 
this  we  may  infer  that  the  living  albumin  always  con- 

345 


THE    WONDERS    OF    LIFE 

tains  the  cyanogen-radical,  and  that  dead  nutritive  al- 
bumin does  not.  The  belief  that  it  is  cyanogen  which 
gives  its  characteristic  vital  properties  to  the  plasm  is 
supported  by  a  number  of  analogies  that  we  find  to 
exist  between  cyanide  compounds,  especially  cyanic  acid 
(C  N  O  H.)  and  the  living  albumin.  Both  bodies  are 
fluid  and  transparent  at  a  low  temperature,  while  they 
set  at  a  higher;  both  of  them  break  up  in  the  presence 
of  water  into  carbonic  acid  and  ammonia ;  both  produce 
urea  by  disassociation  (by  the  intramolecular  surround- 
ing of  the  atoms,  not  by  direct  oxydation).  "The 
similarity  of  the  two  substances  is  so  great,"  says 
Pfliiger,  "that  I  might  describe  cyanic  acid  as  a  semi- 
living  molecule."  Both  substances  grow  in  the  same 
way  by  concatenation  of  the  atoms,  homogeneous  groups 
of  atoms  joining  together  chain-wise  in  large  masses. 

There  is  an  especial  interest  in  connection  with  the 
theory  of  archigony  and  its  physical  basis  in  the  chemi- 
cal fact  that  cyanogen  and  its  compounds — cyanide 
of  potassium,  cyanic  acid,  cyanide  of  hydrogen,  etc. 
— are  only  formed  at  incandescent  heat;  that  is  to  say, 
when  the  requisite  inorganic  nitrogenous  compounds 
are  put  with  glowing  coals,  or  the  mixture  is  heated  to 
incandescence.  Other  essential  constituents  of  albu- 
min, such  as  carburetted  hydrogen  or  alcohol-radical, 
can  be  formed  synthetically  in  heat.  "Thus,"  says 
Pfluger,  "nothing  is  clearer  than  the  possibility  of  the 
formation  of  cyanic  compounds  when  the  earth  was  en- 
tirely or  partially  in  a  state  of  incandescence  or  great 
heat.  We  see  how  extraordinarily  all  the  facts  of  chem- 
istry point  to  fire  as  the  force  that  has  produced  the  con- 
stituents of  albumin  by  synthesis.  Hence  life  was  born 
from  fire,  and  the  chief  conditions  of  its  appearance  are 
associated  with  a  time  when  the  earth  was  a  glowing 
ball  of  fire.  When  we  remember  the  incalculably  long 
period  in  which  the  surface  of  the  earth  was  slowly  cool- 

346 


THE    O  R  I  O  I  X    OF    LIFE 

ing,  we  see  that  cyanogen,  and  the  compounds  that  con- 
tained cyanogen,  and  carbiiretted  hydrogen,  had  j^lcnty 
of  time  and  opportunity  to  follow  out  to  any  extent 
their  great  tendency  to  the  transposition  and  formation 
of  polymeria  (chains  of  atoms),  and,  with  the  co-opera- 
tion of  oxygen  and  afterwards  of  water  and  salts,  to 
evolve  into  the  self-decomposable  albumin  which  is  liv- 
ing matter."  In  regard  to  the  latter  feature,  it  is  well 
to  emphasize  the  fact  that,  as  will  be  understood,  there 
must  have  been  a  long  series  of  chemical  intermediary 
stages  between  the  incandescent  formation  of  cyanogen 
and  the  appearance  of  the  aqueous  living  plasm. 

Pfliiger's  cyanogen  theory  does  not  conflict  with  my 
monera  theory,  but  rather  supplements  it,  by  its  careful 
and  thoroughly  scientific  study  of  a  much  earlier  stage 
of  primitive  biogenesis — in  a  sense,  the  first  period  of 
preparation  for  the  formation  of  albumin.  This  must  be 
well  borne  in  mind  in  view  of  the  attacks  which  have 
lately  been  made  on  it  by  Neumeister  and  other  vital- 
ists;  it  is  supposed  to  be  untenable,  because  "  there  is  an 
impassable  gulf  between  cyanic  compounds  and  pro- 
teids."  This  criticism  is  answered  by  the  living  albu- 
min itself,  which  always  contains  in  its  nitrogenous  de- 
composition products  the  radical  of  cyanide  or  other 
substances  (urea)  that  can  be  artificially  produced  from 
cyanic  compounds.  Another  objection  is  that  "the 
cyanic  compounds  which  were  formed  in  the  heat  must 
have  very  quickly  perished  on  the  subsequent  appear- 
ance of  water."  The  objection  has  no  weight,  since  we 
can  form  no  definite  idea  as  to  the  special  conditions  of 
chemical  activity  in  those  times.  We  can  only  say  that 
the  conditions  during  this  long  period  (embracing  mill- 
ions of  years)  were  totally  different  from  those  of  chemi- 
cal action  at  the  surface  of  the  earth  to-day.  The  real 
ground  of  the  opposition  of  Neumeister  and  other  vital- 
ists  is  their  dualistic  conception  of  nature,  which  will 

347 


THE    WONDERS    OF    LIFE 

maintain  at  all  costs  the  deep  gulf  between  the  organic 
and  inorganic  worlds. 

Max  Verworn,  in  his  General  Physiology,  has  fully  de- 
scribed and  criticised  the  various  theories  of  the  appear- 
ance of  life  on  the  earth.  He  rightly  attributes  a  great 
value  to  Pfliiger's  cyanogen  theory,  because  "it  makes 
a  strictly  scientific  study  of  the  problem  in  close  rela- 
tion to  the  facts  of  physiological  chemistry,  and  goes 
thoroughly  into  detail."  He  agrees  with  Pfiiiger  when 
he  expresses  himself  as  follows:  "I  would  say,  therefore, 
that  the  first  albumin  to  be  formed  was  in  point  of  fact 
living  matter,  endued  with  the  property  in  all  its  radi- 
cals of  attracting  especially  homogeneous  parts  with 
great  force  and  preference,  in  order  to  build  them  chemi- 
cally into  the  molecule,  and  so  grow  indefinitely.  On 
this  view  the  living  albumin  need  not  have  a  constant 
molecular  weight,  because  it  is  a  huge  molecule  in  an 
unceasing  process  of  formation  and  decomposition,  prob- 
ably acting  on  the  ordinary  chemical  molecules  as  a  sun 
does  on  a  small  meteor."  This  theory,  which  I  believe 
to  be  correct,  is  also  maintained  by  many  other  modern 
scientists  who  have  made  a  particular  study  of  the  diffi- 
cult question  of  the  nature  and  origin  of  the  albumi- 
noids. 

Now  that  we  have  described  the  various  modern 
theories  of  archigony  that  are  worth  considering,  and 
recognized  with  Nageli  that  the  original  development 
of  the  organic  from  the  inorganic  is  a  fact,  we  may 
glance  at  the  older  theories  which,  under  the  name  of 
"spontaneous  generation,"  afforded  matter  for  a  good 
deal  of  controversy.  It  is  true  that  they  are  now  al- 
most entirely  abandoned,  but  the  experiments  in  con- 
nection with  them  excited  a  good  deal  of  interest  and 
led  to  many  misunderstandings. 

The  older  hypotheses  of  "spontaneous  generation" 
do  not  bear  on  our  problem  of  archigony  (or  the  first 

348 


THE    ORIGIN    OF    LIFE 

development  of  living  matter  from  lifeless  inorganic 
carbon  compounds)  but  relate  to  the  formation  of  lower 
organisms  out  of  the  putrid  and  decomposing  organic 
elements  of  higher  organisms.  In  order  to  distinguish 
these  hypotheses  from  the  totally  different  theory  of 
archigony,  it  is  better  to  give  them  the  name  of  sapro- 
biosis  (an  earlier  name  was  necrobiosis),  which  means 
the  birth  of  living  from,  dead  (nekron)  or  putrid  (sapron) 
organic  matter.  Saprobiosis  is  preferable,  because  nec- 
robiosis is  better  used  in  a  different  sense,  for  the  dead 
organic  parts  which  gradually  bring  about  the  death  of 
the  living  body  (see  p.  io6).  It  was  believed  in  ancient 
times  that  lower  organisms  could  arise  from  the  dead 
remains  of  higher  organisms,  such  as  fleas  from  manure, 
lice  from  morbid  pustules  in  the  skin,  moths  from  old 
furs,  and  mussels  from  slime  in  the  water.  As  these 
stories  were  supported  by  the  authority  of  Aristotle,  and 
on  that  account  believed  by  St.  Augustine  and  other 
fathers,  and  reconciled  with  the  faith,  they  were  held 
until  the  beginning  of  the  eighteenth  century.  Even  in 
the  year  17 13  the  botanist  Heucherus  stated  that  the 
green  duck-weed  (lemna)  is  only  condensed  grease  from 
the  surface  of  foul  standing  water,  and  that  water-cress 
was  formed  from  it  in  fresh  running  water. 

The  first  scientific  refutation  of  these  old  stories  was 
made  by  the  Italian  physician,  Francisco  Redi,  in  1674, 
on  the  basis  of  very  careful  experiment:  he  was  perse- 
cuted for  "unbelief"  on  that  account.  He  showed  that 
all  these  animals  arose  from  eggs  that  had  been  deposited 
by  female  animals  in  dung,  skin,  fur,  slime,  etc.  But  at 
that  time  the  proof  could  not  be  extended  to  the  tape- 
worms, maw-worms,  and  other  intestinal  animals  {nt- 
tozoa),  which  live  inside  other  animals  (in  the  bowels, 
blood,  brain,  or  liver).  It  was  still  believed  that  these 
arise  from  diseased  parts  of  the  host-animals  in  which 
they  live,  until  about  the  middle  of  the  nineteenth  cen- 

349 


THE    WONDERS    OF    LIFE 

tury.  It  was  not  until  1 840-1 860  that  it  was  shown 
by  the  experiments  of  Siebold,  Leuckart,  Van  Beneden, 
Virchow,  and  other  famous  biologists,  that  all  these  in- 
testinal animals  have  come  from  without  into  the  ani- 
mals they  live  in,  and  propagate  there  by  eggs.  Of 
late  years  the  proof  has  been  applied  all  round. 

On  the  other  hand,  the  hypothesis  of  saprobiosis  re- 
tained its  position  until  quite  recently  for  one  section 
of  the  smallest  and  lowest  organisms,  the  microscopic 
forms  of  life,  invisible  to  the  naked  eye,  which  were 
formerly  called  infusoria,  and  which  we  now  call  by  the 
wider  name  of  protists  or  unicellulars.  When  Leeuwen- 
hoek  discovered  the  infusoria  in  1675  with  the  newly 
invented  microscope,  and  showed  that  they  arise  in 
great  quantities  in  infusions  of  hay,  moss,  flesh,  and 
other  putrid  organic  substances,  it  was  generally  be- 
lieved that  they  were  spontaneously  generated  there. 
The  Abbe  Spallanzani  showed  in  1687  that  no  infusoria 
appear  in  these  infusions  if  they  are  well  boiled  and 
the  vessel  is  carefully  closed ;  the  boiling  kills  the  germs 
in  them,  and  the  exclusion  of  air  prevents  the  entrance 
of  fresh  germs.  In  spite  of  this,  many  microscopists 
still  believed  that  certain  infusoria,  particularly  the  very 
small  and  simple  bacteria,  could  be  born  directly  from 
putrid  or  diseased  tissues  of  organisms,  or  from  decom- 
posing organic  fluids;  the  opinion  was  maintained  by 
Pouchet  at  Paris  in  1858,  and  afterwards  by  Charlton 
Bastian.  The  controversy  about  the  subject  moved  the 
Paris  Academy  in  1858  to  offer  a  prize  for  "careful 
research  that  would  throw  new  light  on  the  question  of 
spontaneous  generation."  It  fell  to  the  famous  Louis 
Pasteur,  who  proved,  by  a  series  of  ingenious  experi- 
ments, that  there  are  everywhere  in  the  atmosphere 
numbers  of  germs  of  microbes  or  microscopic  organisms 
floating  among  the  dust  particles,  and  that  these  grow 
and  reproduce  when  they  reach  water.     Not  only  in- 

350 


THE    ORIGIN    OF    LIFE 

fusoria,  but  also  small  highly  organized  plants  and  ani- 
mals— such  as  lichens,  mosses,  rotifers,  and  tardigrades 
— can  live  for  months  in  a  desiccated  condition,  be  car- 
ried in  all  directions  by  the  wind,  and  reawaken  into 
life  when  they  reach  water.  On  the  other  hand,  Pasteur 
showed  convincingly  that  organisms  never  a])i)ear  in 
infusions  of  organic  substances  when  they  are  sufficient- 
ly boiled  and  the  atmosphere  that  reaches  them  has  been 
chemically  purified.  He  summed  up  the  results  of  his 
rigorous  experiments,  which  were  confirmed  by  Rob- 
ert Koch  and  other  bacteriologists,  and  gave  rise  to 
the  modern  precautions  as  to  disinfection,  in  the 
maxim  :  "  Spontaneous  or  equivocal  generation  is  a 
myth." 

The  famous  experiments  of  Pasteur  and  his  successors 
had  destroyed  the  myth  of  saprobiosis,  but  not  the 
theory  of  archigony.  These  entirely  diflerent  hypoth- 
eses are  still  very  frequently  confused,  because  the  old 
title  of  "spontaneous  generation"  is  used  for  both.  We 
still  read  sometimes  that  the  "unscientific"  belief  in 
abiogenesis  has  been  definitely  refuted  by  these  experi- 
ments, and  that  the  question  of  the  origin  of  life  has 
thus  become  an  insoluble  enigma.  There  is  an  aston- 
ishing superficiality  and  lack  of  discernment  in  such  re- 
marks; they  would  hardly  be  possible  in  any  other 
branch  of  science.  But  in  biology — many  of  its  distin- 
guished representatives  continue  to  say — we  have  only 
to  observe  and  correctly  describe  facts;  the  formation 
of  clear  ideas  and  the  indulgence  in  reflection  on  the 
facts  are  unnecessary  and  dangerous,  and,  therefore, 
to  be  avoided!  It  is  due  to  this  pitiable  condition  of 
biological  methods  of  research  that  our  hypothesis  of 
archigony  is  still  attacked,  or  else  ignored.  Why? 
Because  the  false  hypothesis  of  saprobiosis,  which  has 
absolutely  nothing  in  common  with  it  but  the  name 
"spontaneous   generation,"    has    been    refuted    by    the 

351 


THE    WONDERS    OF    LIFE 

experiments  of  Pasteur  and  his  colleagues!*  These  ex- 
periments prove  nothing  whatever  beyond  the  fact  that 
new  organisms  are  not  formed  in  certain  infusions  of 
organic  matter  —  under  definite,  artificial  conditions. 
They  do  not  even  touch  the  important  and  pressing 
question,  which  alone  interests  us:  "How  did  the 
earliest  organic  inhabitants  of  our  earth,  the  primitive 
organisms,  arise  from  inorganic  compounds?" 

The  great  popularity  of  the  famous  experiments  of 
Pasteur  on  spontaneous  generation,  and  the  unfortunate 
confusion  of  ideas  which  was  caused  by  the  false  inter- 
pretation of  his  results,  make  it  necessary  for  me  to  say 
a  word  on  the  general  value  of  scientific  experiments  in 
many  questions.  Since  Bacon  introduced  experiment 
into  science  three  hundred  years  ago,  and  gave  it  a  logi- 
cal basis,  both  our  speculative  knowledge  of  nature  and 
the  practical  application  of  our  knowledge  have  made 
remarkable  progress.  New  methods  of  research  made  it 
possible  for  modem  workers  to  penetrate  far  more  deeply 
into  the  nature  of  phenomena  than  the  older  thinkers 
had  done,  who  had  no  knowledge  of  experiment.  Es- 
pecially in  the  nineteenth  century  the  development  of 
the  experimental  method,  or  the  putting  of  a  question  to 
nature,  led  to  enormous  advances  in  the  various  sciences. 

In  the  subject  we  are  considering  the  question  to  be 
put  to  nature  is:  "Under  what  conditions  and  in  what 
manner  is  living  matter  (or  plasm)  formed  from  lifeless 
inorganic  compounds?"  We  may  confidently  assume 
that  in  the  period  when  archigony  took  place  —  the 
time  when  organic  life  first  appeared  on  the  cooled 
surface  of  the  earth,  at  the  beginning  of  the  Laurentian 
Age — the  conditions  of  existence  were  totally  different 

'  I  may  remind  the  English  reader  that  the  chosen  ecclesias- 
tical champion  against  Haeckel  in  this  country,  the  Rev.  F. 
Ballard,  made  this  extraordinary  fallacy  the  very  pith  of  his 
"scientific"  attack  on  monism. — Trans. 


THE    (J  R  i  G  1  N    OF    L  1  F  E 

from  what  they  are  now;  but  we  are  very  far  from 
having  a  clear  idea  of  what  they  were,  or  from  being  able 
to  reproduce  them  artificially.  We  are  just  as  far  from 
having  a  thorough  chemical  acquaintance  with  the  al- 
buminous compounds  to  which  plasm  belongs.  We  can 
only  assume  that  the  ])lasma  -  molecule  is  extremely 
large,  and  made  up  of  more  than  a  thousand  atoms,  and 
that  the  arrangement  and  connection  of  the  atoms  in 
the  molecule  are  very  complicated  and  unstable.  But 
of  the  real  features  of  this  intricate  structure  we  have 
as  yet  no  conception.  As  long  as  we  are  ignorant  of 
this  complex  molecular  structure  of  albumin,  it  is  use- 
less to  attempt  to  produce  it  artificially.  Yet  in  this 
position  of  the  matter  we  would  seek  to  produce  that 
great  wonder  of  life,  the  plasm,  artificially,  and  when  the 
experiment  miscarries  (as  we  should  expect)  we  cry  out: 
"Spontaneous  generation  is  impossible." 

When  we  carefully  consider  the  intelligent  experiments 
that  have  been  made  in  regard  to  archi^ony  in  the  light 
of  these  facts,  it  is  clear  that  their  negative  result  does 
not  in  the  slightest  degree  affect  our  question.  The 
much-admired  experiments  of  Pasteur  and  his  colleagues 
prove  merely  that  in  certain  artificial  conditions  infusoria 
are  not  formed  in  decomposing  organic  compounds  (or 
the  dead  tissues  of  highly  organized  histona) ;  they  can- 
not possibly  prove  that  saprobioses  of  this  kind  do  not 
take  place  under  other  conditions.  They  tell  us  noth- 
ing whatever  about  the  possibility  or  reality  of  archig- 
ony;  in  the  form  in  which  I  put  the  scientific  hypoth- 
esis in  1866  it  is  completely  untouched  by  all  these 
experiments.  It  remains  intact  as  the  first  attempt  to 
give  a  provisional  reply — if  only  in  the  form  of  a  tem- 
porary hypothesis — on  the  basis  of  modern  science  to 
one  of  the  chief  questions  of  natural  philosophy. 

In  my  General  Morphology  (1866),  and  afterwards  in 
my  Biological  Studies  on  the  M  oner  a  and  other  P  rot  i  sis, 

aa  353 


THE    WONDERS    OF    LIFE 

and  the  first  volume  of  my  Systematic  Phytogeny  (1894), 
I  attempted  to  sketch  in  detail  the  stages  of  the  process 
to  which  I  give  the  name  of  archigony.  I  distinguished 
two  principal  stages — autogony  (the  formation  of  the  first 
living  matter  from  inorganic  nitrogenous  carbon-com- 
pounds) and  plasmogony  (the  formation  of  the  first  indi- 
vidualized plasm;  the  earliest  organic  individuals  in  the 
form  of  monera).  In  more  recent  efforts  I  have  made 
use  of  the  important  results  reached  by  Nageli  (1884) 
in  his  investigations  of  the  same  subject.  In  regard  to 
some  important  points  relating  to  the  chemico-physical 
part  of  the  question,  Nageli  has,  in  his  Mechanico- 
physiological  Theory  of  Evolution  (chapter  ii.),  gone  more 
into  the  details  of  the  process  of  archigony.  To  the 
earliest  living  things,  which  were  formed  by  "unicellu- 
lar organization"  of  the  plasm  out  of  simple  inorganic 
compounds,  he  gives  the  name  of  prohia  or  probionta, 
and  thinks  that  these  had  an  even  simpler  structure 
than  my  monera.  This  view  seems  to  rest  on  a  mis- 
understanding. Nageli  does  not  strictly  follow  my 
definition,  "organisms  without  organs"  (that  is  to  say, 
structureless  living  particles  of  plasm  without  morpho- 
logical differentiation) ,  but  he  has  in  mind  the  individual 
rhizopod-like  organisms  which  I  had  at  first  described  as 
monera — protamceba,  protogenes,  protoinyxa,  etc.  In  my 
present  view  the  chromacea,  or  plasmodomous  phyto- 
monera,  are  rauch  more  important  than  these  plasmoph- 
agous  zoomonera.  It  is  curious  that  Nageli  does  not 
make  thorough  use  of  their  primitive  organization  for 
the  establishment  of  his  theory,  although  he  has  had  the 
great  merit  of  describing  these  most  primitive  of  all 
living  organisms  as  unicellular  algae  (1842).  As  a  matter 
of  fact,  the  simplest  chromacea  (chroococcus  and  related 
forms)  approach  so  closely  to  his  hypothetical  probia  or 
probionta  that  the  only  things  we  can  regard  as  the 
rudiments  of  organization  in  the  chroococcacea  are  the 

354 


THE    ORIGIN    OF    LIFE 

secretion  of  a  protective  membrane  about  the  homo- 
geneous plasma-globule  and  the  separation  of  the  blue- 
ish-green  cortical  zone  from  the  colorless  central  gran- 
ule. The  more  important  of  the  further  conclusions  of 
Nageli  are  those  which  relate  to  the  mode  of  the  primi- 
tive abiogenesis  and  the  frequent  repetition  of  this 
physical  process. 

Recently  Max  Kassowitz,  in  the  second  volume  of  his 
General  Biology  (1899),  has  gone  fully  into  the  various 
stages  of  the  process  of  archigony,  as  a  sequel  to  his 
metabolic  theory  of  the  building  up  and  decay  of  plasm, 
from  the  point  of  view  of  physiological  chemistry.  He 
says  very  truly  that  the  development  of  living  from  life- 
less matter  must  not  be  conceived  as  a  sudden  leap ;  the 
very  complicated  chemical  unities  which  now  form  the 
basis  of  life  have  been  slowly  and  gradually  evolved 
during  an  incalculably  long  period  by  the  way  of  substi- 
tution for  simpler  compounds.  We  may  join  these  views 
— which  generally  accord  with  my  earlier  deductions — 
with  Pfluger's  cyanogen  theory,  and  so  draw  up  the 
following  theses : 

I.  A  preliminary  stage  to  archigony  is  the  formation  ' 
of  certain  nitrogenous  carbon-compounds  which  may  be 
classed  in  the  cyanic  group  (cyanic  acid,  etc.).  2.  When 
the  crust  of  the  earth  stiffened,  water  was  formed  in  the 
fluid  condition;  under  its  influence,  and  in  consequence 
of  the  great  changes  in  the  carbonic-acid  laden  atmos- 
phere, a  series  of  complicated  nitrogenous  carbon- 
compounds  were  formed  from  these  simple  cyanic 
compounds,  and  these  first  produced  albumin  (or  pro- 
tein). 3.  The  molecules  of  albumin  arranged  themselves 
in  a  certain  way,  according  to  their  unstable  chemical 
attractions,  in  larger  groups  of  molecules  (j)leona  or 
micella).  4.  The  albumin-micella  coml)incd  to  form 
larger  aggregations,  and  produced  homogeneous  plasma- 
granules  (plassonella).     5.  As  they  grew  the  plassonella 

355 


THE    WONDERS    OF    LIFE 

divided,  and  formed  larger  plasma-granules  of  a  homo- 
geneous character;  monera  (=:probionta).  6.  In  con- 
sequence of  surface-strain  or  of  chemical  differentiation, 
there  took  place  a  separation  of  the  firmer  cortical 
layer  (membrane)  from  the  softer  marrow  layer  (central 
granule),  as  in  many  of  the  chromacea.  7.  Afterwards 
the  simplest  (nucleated)  cells  were  formed  from  these 
unnucleated  cytodes,  the  hereditary  mass  of  the  plasm 
gathering  within  the  monera  and  condensing  into  a  firm 
nucleus. 

It  is  an  interesting,  but  at  present  unanswered, 
question  whether  the  process  of  archigony  only  occurred 
once  in  the  course  of  time  or  was  frequently  repeated. 
Reasons  can  be  given  for  both  views.  Pfliiger  says: 
"In  the  plant  the  living  albumin  only  continues  to  do 
what  it  has  done  ever  since  its  origin — constantly  to 
regenerate  itself  or  to  grow;  hence  I  believe  that  all  the 
albumin  in  the  world  comes  from  that  source.  On  that 
account  I  doubt  if  spontaneous  generation  takes  place  in 
our  time.  Moreover,  comparative  biology  directly  shows 
that  all  life  has  come  from  one  single  root."  However, 
this  view  does  not  exclude  the  possibility  of  the  chemical 
process  of  spontaneous  plasmodomism  having  been  fre- 
quently repeated — under  like  conditions — in  the  same 
form  in  primordial  times. 

On  the  other  side,  Nageli  especially  has  pointed  out 
that  there  is  no  reason  to  prevent  us  from  thinking  that 
archigony  was  repeated  several  times,  even  down  to  our 
own  day.  Whenever  the  physical  conditions  for  the 
chemical  process  of  plasmodomism  were  given,  it  might 
be  repeated  anywhere  at  any  time.  As  to  locality,  the 
sea-shore  probably  affords  the  most  favorable  conditions ; 
as,  for  instance,  on  the  surface  of  fine  moist  sand  the 
molecular  forces  of  matter  in  all  its  conditions — gaseous, 
fluid,  viscous,  and  solid — find  the  best  conditions  for 
acting  on  each  other.     It  is  a  fact  that  to-day  all  the 

356 


THE    ORIGIN    OF    LIFE 

various  evolutionary  forms  of  living  matter — from  the 
simplest  moneron  (chroococcus)  to  the  plain  nucleated 
cell,  from  this  to  the  highly  organized  cell  of  the  radio- 
laria  and  infusoria,  from  the  simjile  ovum  to  the  most 
elaborate  tissue-stnicture  in  tlic  higher  ])lants  and 
animals,  from  the  am])hioxus  to  man — come  in  an  order 
of  succession.  There  are  only  two  ways  of  explaining 
this  fact:  either  the  simplest  living  organisms,  the 
chromacea  and  bacteria,  the  jjalmella  and  amoeba?,  have 
remained  unchanged  or  made  very  little  advance  in 
organization  since  the  beginning  of  life — more  than  a 
hundred  million  years;  or  else  the  phylogenetic  process 
of  their  transformation  has  been  frequently  repeated  in 
the  course  of  this  period,  and  is  being  repeated  to-day. 
Even  if  the  latter  were  the  case,  we  should  hardly  be  in 
a  position  to  learn  it  by  direct  observation. 

Assuming  that  the  simplest  organisms  are  still  fonned 
by  abiogenesis,  the  direct  observation  of  the  process 
would  probably  be  impossible,  or  at  least  extremely 
difficult,  for  the  following  reasons:  i.  The  earliest  and 
simplest  organisms  are  most  probably  globular  particles 
of  plasm,  without  any  visible  structure,  like  the  simplest 
living  chromacea  {chroococcus).  2.  These  plasmodom- 
ous  monera  cannot  be  distinguished  from  the  chromo- 
plasts  (chlorophyll-granules),  which  live  inside  plant- 
cells,  and  may  continue  after  the  death  of  the  cells 
to  multiply  independently  by  cleavage.  3.  We  must 
admit  with  Nageli  that  the  original  size  of  these  pro- 
bionta  (in  spite  of  the  relatively  colossal  size  of  their 
molecules)  is  very  small — much  too  small  to  come  within 
the  range  of  the  best  microscope.  4.  In  the  same  way 
the  primitive  metabolism  and  the  slow,  simple  growth  of 
these  monera  would  not  come  within  direct  observation. 
5.  As  a  matter  of  fact,  we  do  often  find  in  stagnant 
water,  and  in  the  sea,  tiny  granules  which  consist,  or 
seem  to  consist,  of  plasm.     We  usually  regard  them  as 

357 


THE    WONDERS    OF    LIFE 

detached  portions  of  dead  animals  or  plants;  little 
isolated  chlorophyll-granules  that  may  be  found  every- 
where are  looked  upon  as  rejected  products  of  vegetal 
cells.  But  who  could  refute  the  assumption  that  they 
are  really  plassonella  or  young  monera,  which  grow 
slowly  and  unite  with  similar  particles  to  form  larger 
plasmic  bodies  ? 

It  is  often  objected  to  our  naturalistic  and  monistic 
conception  of  archigony  that  we  have  not  yet  succeeded 
in  forming  albuminous  bodies,  and  especially  plasm,  in 
our  chemical  laboratories  by  artificial  synthesis;  from 
this  the  perverse  dualistic  conclusion  is  drawn  that  it  is 
only  supernatural  vital  forces  that  can  do  this.  It  is 
forgotten  that  we  do  not  yet  know  the  complicated 
structure  of  albuminous  bodies,  and  that  we  do  not  yet 
know  what  really  happens  inside  the  green  chlorophyll- 
granules  which  in  every  plant-cell  convert  the  radiant 
energy  of  sunlight  into  the  virtual  energy  of  the  new- 
formed  plasm.  How  can  we  be  expected  to  reproduce 
synthetically,  with  the  imperfect  and  crude  methods  of 
present  chemistry,  an  elaborate  chemical  process  the 
nature  of  which  is  not  analytically  known  to  us  ?  How- 
ever, the  worthlessness  of  this  sceptical  objection  is 
obvious:  we  can  never  claim  that  a  natural  process  is 
supernatural  because  we  cannot  artificially  reproduce  it. 


XVI 

THE  EVOLUTION  OF  LIFE 

Inorganic  and  organic  evolution — Biogenesis  and  cosmogenesis — 
Mechanical  svolution — Mechanics  of  phylogenesis — Theory 
of  selection — Theory  of  idioplasm — Phyletic  vital  f(<rce — 
Theory  of  germ-plasm — Progressive  heredity — Comparative 
morphology — Germ-plasm  and  hereditary  matter — Theory 
of  mutation — Zoological  and  botanical  transformism — 
Neo-Lamarckism  and  Neo-Darwinism — Mechanics  of  onto- 
genesis— Biogenetic  law — Tectogenetic  ontogeny — Experi- 
mental evolution — Monism  and  biogeny. 

I  FULLY  explained  in  my  General  Morphology  (1866) 
the  profound  importance  of  the  science  of  evolution 
in  relation  to  our  monistic  philosophy.  A  popular  synop- 
sis of  this  is  given  in  my  History  of  Creation,  and  is 
briefly  repeated  in  the  thirteenth  chapter  of  the  Riddle. 
I  must  refer  the  reader  to  these  works,  especially  the 
latter,  and  confine  myself  here  to  a  consideration  of 
some  of  the  principal  general  questions  of  evolution  in 
the  light  of  modern  science.  The  first  thing  to  do  is  to 
compare  the  conflicting  views  on  the  nature  and  signifi- 
cance of  biogenesis  which  still  face  each  other  at  the 
beginning  of  the  twentieth  century. 

The  essential  unity  of  inorganic  and  organic  nature, 
which  I  endeavored  to  establish  in  the  second  book  of 
the  General  Morphology,  and  the  significance  of  which  I 
explained  in  the  fourteenth  chapter  of  the  Riddle,  is 
found  through  the  whole  course  of  its  development,  in 
the  causes  of  phenomena  and   their  laws.     Hence,  in 

359 


THE    WONDERS    OF    LIFE 

dealing  with  the  evolution  of  organisms,  we  reject 
vitalism  and  dualism,  and  maintain  our  conviction  that 
it  can  always  be  traced  to  physical  forces  (and  especially 
chemical  energy).  As  we  regard  plasm  as  the  basis  of 
it  (chapter  vi.),  we  may  say  that  organic  evolution 
depends  on  the  mechanics  and  chemistry  of  the  plasm. 
We  postulate  no  supernatural  vital  force  for  the  ex- 
planation of  physiological  functions,  and  we  are  just  as 
far  from  admitting  it  as  regulator  or  agency  of  the 
biogenetic  process. 

If  we  understand  by  biogeny  the  sum  total  of  the 
organic  evolutionary  processes  on  our  planet,  by  geogeny 
the  processes  at  work  in  the  formation  of  the  earth  itself, 
and  by  cosmogony  those  that  produced  the  whole  world, 
biogeny  is  clearly  only  a  small  part  of  geogeny,  and  this 
in  turn  only  a  small  section  of  the  vast  science  of  cosmog- 
ony. This  important  relation  is  evident  enough,  yet 
often  overlooked ;  it  holds  both  of  time  and  space.  Even 
if  we  suppose  that  the  biogenetic  process  occupied  more 
than  a  hundred  million  years,  this  period  is  probably 
much  shorter  than  that  which  our  planet  has  needed  for 
its  development  as  a  cosmic  body — from  the  first  detach- 
ment of  the  nebular  ring  from  the  shrinking  body  of  the 
sun  to  its  condensation  into  a  rotating  sphere  of  gas,  and 
from  this  to  the  formation  of  the  incandescent  globe,  the 
stiffening  of  the  crust  at  its  surface,  and  finally  the  down- 
pour of  fluid  water.  It  was  not  until  this  last  stage  that 
carbon  could  begin  its  organogenetic  activity  and  proceed 
to  the  formation  of  plasm.  But  even  this  long  geogenetic 
process  is,  as  regards  space  and  time,  only  a  very  small 
part  of  the  illimitable  history  of  the  world.  If  we  further 
assume  that  organic  life  develops  on  other  cosmic  bodies 
{Riddle,  chapter  xx.)  in  the  same  way  as  on  our  earth 
under  like  conditions,  the  whole  sum  of  all  these  bio- 
genetic processes  is  only  a  small  part  of  the  all-embracing 
cosmogenetic    process.     The    vitalistic    belief    that   its 

360 


THE    EVOLUTION    OF    LIFE 

mechanical  course  was  interrupted  from  time  to  time  by 
the  supernatural  creation  of  or^^anisms  is  opposed  to 
pure  reason,  the  unity  of  nature,  and  the  law  of  substance. 
We  must,  therefore,  hold  fast  above  all  to  the  conviction 
that  all  biogenetic  processes  are  just  as  reducible  to  the 
mechanics  of  substance  as  all  other  natural  phenomena. 

The  mechanical  and  natural  character  of  the  develop- 
ment of  inorganic  nature,  the  earth  and  the  whole 
material  world,  was  established  mathematically  at  the 
end  of  the  eighteenth  century  by  the  great  atheist 
Laplace  in  his  Mccanique  Celeste  (1799).  The  similar 
cosmogony  which  Kant  had  expounded  in  1755  in  his 
General  Natural  History  and  Theory  of  the  Heavens  only 
obtained  recognition  at  a  later  date  {Riddle,  chapter  xiii.). 
But  the  possibility  of  giving  a  mechanical  explanation  of 
organic  nature  was  not  seen  until  Darwin  provided  a 
solid  foundation  for  the  theory  of  descent  by  his  theor}'' 
of  selection  in  1859.  I  made  the  first  comprehensive 
attempt  to  do  this  in  1866  in  my  General  Morphology,  the 
aim  of  which  is  expressed  in  the  title:  "General  out- 
lines of  the  science  of  organic  forms,  mechanically 
grounded  on  Darwin's  improvement  of  the  theory  of 
descent."  Especially  in  the  second  volume  of  the  work, 
the  "General  Evolution  of  Organisms,"  I  endeavored 
to  show  that  both  sections  of  the  science,  ontogeny  (or 
embryology)  and  ph^dogeny,  can  be  reduced  to  physio- 
logical activities  of  the  plasm,  and  so  explained  mechani- 
call3^  in  the  wider  meaning  of  the  word. 

When  I  stated  the  nature  and  the  aim  of  phylogeny  in 
1866,  most  biologists  regarded  my  attempt  as  unjusti- 
fiable, as  they  did  Darwinism  itself,  of  which  it  was  a 
natural  consequence.  Even  the  famous  Emil  Dubois- 
Reymond,  to  whom  as  a  physiologist  it  should  have 
been  welcome,  described  it  as  "a  poor  romance";  he 
compared  my  first  attempts  to  construct  the  genealogical 
tree  of  the  organic  classes,  on  the  evidence  of  paleontol- 

361 


THE    WONDERS    OF    LIFE 

ogy,  comparative  anatomy,  and  ontogeny,  to  the  hypo- 
thetical labors  of  philologists  to  draw  up  the  genealogical 
tree  of  the  legendary  Homeric  heroes.     As  a  matter  of 
fact,  I  had  myself  described  my  imperfect  effort  as  mere- 
ly a  provisional  sketch,  as  a  temporary  hypothesis  that 
would  open  the  way  for  later  and  better  research.     A 
single  glance  at  the  immense  literature  of  phylogeny 
to-day  shows  how  much  has  been  done  vSince  in  this 
province,  and  how  far  we  have  advanced  in  the  estab- 
lishment of  the  features  of  evolution  by  means  of  the 
united  labors  of  numbers  of  able  paleontologists,  anat- 
omists, and  embryologists.     Ten  years  ago  I  attempted, 
in  the  three  volumes  of  my  Systematic  Phylogeny,  to 
give  a  comprehensive  statement  of  the  results  attained. 
My  chief  aim  was,   on  the  one  hand,   to  construct  a 
natural  system  of  organisms  on  the  basis  of  their  an- 
cestral history,   and   on  the  other  hand  to  prove  the 
mechanical  character  of  the  phylogenetic  process.     All 
the  activities  of  organisms  which  are  at  work  in  the 
transformation  of  species  and  the  production  of  new  ones 
in  the  struggle  for  existence  may  be  reduced  to  their 
physiological    functions — to  growth,  nutrition,  adapta- 
tion, and  heredity;  and  these  again  to  the  mechanics 
'    ^and  chemistry  of  the  plasm.     The  struggle  for  life  is 
itself  a  mechanical  process,  in  which  natural  selection 
uses  the  disproportion  between  the  excess  of  germs  and 
the  restricted  means  of  existence,  in  conjunction  with  the 
variability  of  species,  in  order  to  produce  new  purposive 
structures  mechanically  and  without  any  preconceived 
design.     This  teleological  mechanicism  has  no  need  of  a 
mysterious  design  or  finality;  it  takes  its  place  in  the 
general  order  of  mechanical  causality  which  controls  all 
the  processes  in  the  universe.     Natural  finality  is  only  a 
special  instance  of  mechanical  causality.     The  one  is 
subordinate  to  the  other,  not  opposed  to  it,  as  Kant 
would  have  it. 

3<52 


THE    EVOLUTION    OF    LIFE 

The   effort   that   the  great   Lamarck   made   in    1809, 
in  his  Philosophie  Zoologiqiic,  to  establish  transformism 
deserves  high  appreciation  from  monists,  because  it  was 
the  first  attempt  to  give  a  natural  explanation  of  the 
origin  of  the  countless  species  of  organic  forms  which 
inhabit  our  planet.     Up  to  that  time  it  had  been  the 
fashion  to  attribute  their  origin  to  a  miraculous  interven- 
tion of  the  Creator.     This  metaj^hysical  creationism  had 
now  to  face  physical  evolutionism.     Lamarck  explained 
the  gradual  formation  of  organic  species  l)v  the  inter- 
action of  two  physiological  functions — adaptation  and 
heredity.     Adaptation  consists  in  the  imjjrovement  oT" 
organs   by   use,   and   degeneration  by   disuse;  heredity 
acts    by    transmitting    the    features    thus    acquired    to 
posterity.     New  species  arise  by  physiological  transfor- 
mation  from   older  species.     The   fact   that   this  great 
thought  was   overlooked   for  half  a   century   docs   not 
detract    from   its   profound    significance.     But    it    onlv 
obtained  general  recognition  when  Darwin  had  supple- 
mented it  and  filled  up  its  causal  gaps  by  the  theorv  of 
selection  in  1859.     Apart  from  this  specifically  Darwin- 
ian feature  (whether  it  be  true  or  not),  the  fundamental 
idea  of  transformism  is  now  generally  received ;  it  is  ad- 
mitted to-day  even  by  metaphysicians  who  maintained  a 
spirited  opposition  to  it  thirty  years  ago.     The  fact  of 
the  progressive  modification  of  species  is  only  intelligible 
on  Lamarck's  theory  that  the  actual   species   are   the 
transformed  descendants  of  older  species.     In  spite  of 
all  the  learning  and  zeal  with  which  the  theory  has  been 
attacked,  it  has  proved  irrefutable;  nor  can  any  one 
suggest  a  better  theory  to  replace  it.     This  may  he  said 
particularly  of  its  chief  consequence — the  descent  of  man 
from  a  series  of  other  mammals  (proximately  from  the 
apes). 

The  high  value  of  Darwin's  theory  of  selection  for  the 
monistic  biology  is  now  acknowledged  by  all  competent 


THE    WONDERS    OF    LIFE 

and  impartial  authorities  on  the  science.  In  the  course 
of  the  forty-four  years  since  it  found  its  way  into  every 
branch  of  biology,  it  has  been  employed  in  more  than  a 
hundred  large  works  and  several  thousand  essays  in  ex- 
plaining biological  phenomena.  This  alone  is  enough 
to  show  its  profound  importance.  Hence  it  is  mere 
ignorance  of  the  subject  and  its  literature  to  say,  as  has 
been  done  several  times  of  late,  that  Darwinism  is  in 
decay,  or  even  "dead  and  buried."  However,  absurd 
writings  of  this  kind  (such  as  Dennert's  At  the  Death-bed 
of  Darwinism)  have  a  certain  practical  influence,  be- 
cause they  fall  in  with  the  prevailing  superstition  in 
theology  and  metaphysics.  Unfortunately,  they  also 
seem  to  obtain  notice  from  the  circumstance  that  a  few 
botanists  persistentlly  attack  the  Darwinian  theory. 
One  of  the  most  conspicuous  of  these  is  Hans  Driesch, 
who  affirms  that  all  Darwinists  (and  therefore  the  great 
majority  of  modern  biologists)  have  softening  of  the 
brain,  and  that  Darwinism  is  (like  Hegel's  philosophy) 
the  delusion  of  a  generation.  The  arrogance  of  this  con- 
ceited writer  is  about  equal  to  the  obscurity  of  his  bio- 
logical opinions,  the  confusion  of  which  is  covered  by  a 
series  of  most  extravagant  metaphysical  speculations. 
All  these  attacks  have  lately  been  met  very  ably  by 
Plate  in  his  work,  On  the  Significance  of  the  Darwinian 
Principle  of  Selection  and  the  Problem  of  the  Foundation 
of  Species  (second  edition,  1903).  The  most  thorough  of 
recent  defences  of  Darwinism  is  that  made  by  August 
Weismann  in  his  Lectures  on  the  Theory  of  Descent  (1902) 
and  other  works.  But  the  distinguished  zoologist  goes 
too  far  when  he  seeks  to  prove  the  omnipotence  of 
selection  and  wishes  to  ground  it  on  an  untenable  molec- 
ular hypothesis  —  the  theory  of  germ-plasm,  which  we 
will  consider  presently.  Apart  from  these  or  other 
exaggerations,  we  may  say  with  Weismann  that  La- 
marck's theory  of  descent  received  a  sound  causal  basi^ 

364 


THE    E  V  0  L  U  T  I  O  N    OF    LIFE 

by  Darwin's  theory  of  selection.  Its  real  foundations 
are  these  three  phenomena:  heredity,  adaptation,  and 
the  struggle  for  existence.  All  three  are,  as  I  have 
often  said,  of  a  purely  mechanical  and  not  a  teleological 
nature.  Heredity  is  closely  bound  up  with  the  physio- 
logical function  of  rcj)roduction,  and  adaptation  with 
nutrition;  the  struggle  for  life  follows  logically  and 
mathematically  from  the  disproportion  between  the 
number  of  potential  individuals  (germs)  and  of  actual 
individuals  that  grow  to  maturity  and  proi)agate  the 
species. 

When  I  had,  in  my  General  Morpholof^y,  endeavored 
to  gain  acceptance  for  Darwin's  theory  of  selection,  and 
had  presented  evolution  as  a  comprehensive  theory  from 
the  point  of  view  of  the  monistic  philosophy,  a  number 
of  works,  sometimes  of  value,  appeared,  which  made 
special  studies  of  the  various  parts  of  the  immense  prov- 
ince. Eighteen  years  afterwards  a  greater  work  was 
published,  which  started  from  the  same  monistic  prin- 
ciples, but  reached  the  same  conclusion  by  a  difTerent 
way.  In  1884  Carl  Nageli,  one  of  our  ablest  and  most 
philosophic  botanists,  issued  his  M echanical- physiological 
Theory  of  Evolution.  This  interesting  book  consists  of 
various  parts.  It  is  especially  notable  that  evolution  is 
presented  in  it  as  the  one  possible  and  natural  theorv  of 
the  origin  of  species ;  even  morphology  and  classification 
are  treated  explicitly  as  " phylogenetic  sciences."  The 
chapter  on  archigony — a  dark  and  dangerous  problem 
that  is  generally  avoided  by  scientists! — is  one  of  the 
best  that  has  been  written  on  the  sul)ject.  On  the  other 
hand,  Nageli  rejects  Darwin's  theory  of  selection  alto- 
gether, and  would  ex])lain  the  origin  of  species  by  an 
inner  "definitely  directed  variation,"  independently  of 
the  conditions  of  existence  in  the  outer  world.  As  Weis- 
mann  has  properly  observed,  this  internal  principle  of 
evolution,  which  dispenses  with  adaptation  in  the  true 

3^5 


THE    WONDERS    OF    LIFE 

sense  of  the  word,  is  at  the  bottom  merely  a  "phyletic 
vital  force."  It  is  not  made  more  acceptable  by  Nageli 
when  he  builds  up  a  subtle  metaphysical  system  on  it 
and  postulates  a  special  "principle  of  isagitation."  But 
the  idioplasm  theory  he  connects  with  it  is  of  some  value, 
since  it  goes  more  fully  into  the  differentiation  of  the 
cell-plasm  into  two  physiologically  different  parts — the 
idioplasm  of  the  hereditary  matter  and  the  trophoplasm 
as  nutritive  matter  of  the  cell. 

The  vitalist  and  teleological  idea  of  an  internal  prin- 
ciple of  evolution,  that  determines  the  origin  of  animal 
and  plant  species  independently  of  the  environment  and 
its  conditions,  is  not  only  found  in  the  "mechanical- 
physiological"  theory  of  Nageli,  but  also  in  sev^eral 
other  attempts  to  explain  the  agencies  of  the  transfor- 
mation of  species.  All  these  efforts  are  welcomed  by 
the  academic  philosophers  with  their  Kantist  dualism 
(mechanicism  on  the  right,  teleology  on  the  left),  and 
who  are  particularly  anxious  to  save  the  supernatural 
element,  Reinke's  "cosmic  intelligence,"  or  the  wisdom 
of  the  Creator,  or  the  divine  creative  thought.  All  these 
dualistic  and  teleological  efforts  have  the  same  fault: 
they  overlook,  or  fail  to  appreciate  properly,  the  im- 
mense influence  of  the  environment  on  the  shaping  and 
modification  of  organisms.  When,  moreover,  they  deny 
progressive  heredity  and  its  connection  with  functional 
adaptation,  they  lose  the  chief  factor  in  transformation. 
This  applies  also  to  the  theory  of  germ-plasm. 

The  desire  to  penetrate  deeper  into  the  mysterious 
processes  that  take  place  in  the  plasm  in  the  physio- 
logical activities  of  heredity  and  adaptation  has  led  to 
the  formulation  of  a  number  of  molecular  theories.  The 
chief  of  these  are  the  pangenesis  theory  of  Darwin  (1878), 
my  own  perigenesis  theory  (1876),  the  idioplasm  theory 
of  Nageli  (1884),  the  germ-plasm  theory  of  Weismann 
(1885),  the  mutation  theory  of  De  Bries,  etc.     As  I  have 

366 


THE    EVOLUTION    OF    L  1  I"  E 

already  dealt  with  these  in  the  sixth  chai)tcr  (as  well  as 
in  the  ninth  chapter  of  the  History  of  Creation),  I  may 
refer  the  reader  thereto.  None  of  these  or  similar  at- 
tempts has  completely  solved  the  very  difficult  problems 
in  question,  and  none  of  them  has  been  generally  re- 
ceived. There  is,  however,  one  of  them  that  we  must 
consider  more  closely,  because  it  is  not  only  regarded 
by  many  biologists  as  the  greatest  advance  of  the  theory 
of  selection  since  Darwin,  but  it  also  touches  the  roots 
of  several  of  the  chief  problems  of  biogeny.  I  mean  the 
much-discussed  germ-plasm  theory  of  August  Weis- 
mann  (of  Freiburg),  one  of  our  most  distinguished  zoolo- 
gists. He  has  not  only  promoted  the  theory  of  de- 
scent by  his  many  writings  during  the  last  thirty  3'ears, 
but  has  also  put  in  its  proper  light  the  great  importance 
and  entire  accuracy  of  the  theory  of  selection.  But,  in 
his  efforts  to  provide  a  molecular-physiological  basis  for 
it,  he  has  proceeded  by  way  of  metaphysical  speculation 
to  frame  a  quite  untenable  theory  of  the  plasm.  While 
fully  recognizing  the  ability  and  consistency  and  the 
able  treatment  which  Weismann  has  shown,  I  am  com- 
pelled once  more  to  dissent  from  him.  His  ideas  have 
recently  been  completely  refuted  by  Max  Kassowitz 
(1902)  in  his  General  Biology,  and  Ludwig  Plate  in  the 
work  I  mentioned  on  the  Darwinian  principle  of  selec- 
tion. We  need  not  go  into  the  details  of  the  complicated 
hypothesis  as  to  the  molecular  structure  of  the  plasm 
which  Weismann  has  framed  in  support  of  his  theory  of 
heredity — his  theory  of  bio]:)hora,  determinants,  ideas, 
etc. — because  they  have  no  theoretical  basis  and  are  of 
no  practical  use.  But  we  must  pass  some  criticism  on 
one  of  their  chief  consequences.  In  the  interest  of  his 
complicated  hypotheses,  Weismann  denies  one  of  T^a- 
marck's  most  important  principles  of  transmutation — 
namely,  the  inheritance  of  acquired  characters. 

When  I  made  the  first  attempt  in  1866  to  formulate 

367 


THE    WONDERS    OF    LIFE 

the  phenomena  of  heredity  and  adaptation  in  definite 
laws  and  arrange  these  in  series,  I  drew  a  distinction 
between  conservative  and  progressive  heredity  (chapter 
ix.,  History  of  Creation).  Conservative  heredity,  or  the 
inheritance  of  inherited  characters,  transmits  to  pos- 
terity the  morphological  and  physiological  features 
which  each  individual  has  received  from  his  parents. 
Progressive  heredity,  or  the  inheritance  of  acquired 
characters,  transmits  to  offspring  a  part  of  those  features 
which  were  acquired  by  the  parents  in  the  course  of  their 
individual  lives.  The  chief  of  these  are  the  characters 
that  are  caused  by  the  activity  of  the  organs  themselves. 
Increase  in  the  use  of  the  organs  causes  a  greater  access 
of  nourishment  and  promotes  their  growth;  decrease  in 
the  exercise  of  organs  has  the  contrary  effect.  We  have 
examples  at  hand  in  the  modification  of  the  muscles  or 
the  eyes,  the  action  of  the  hand  or  throat  in  painting  or 
singing,  and  so  on.  In  these  and  all  the  arts  the  rule 
is:  Practice  makes  perfect.  But  this  applies  almost 
universally  to  the  physiological  activity  of  the  plasm, 
even  its  highest  and  most  astounding  function — thought ; 
the  memory  and  reasoning  capacity  of  the  phronema  are 
improved  by  constant  exercise  of  the  cells  which  com- 
pose this  organ,  just  as  we  find  in  the  case  of  the  hands 
and  the  senses. 

Lamarck  recognized  the  great  morphological  signifi- 
cance of  this  physiological  use  of  the  organs,  and  did 
not  doubt  that  the  modification  caused  was  transmitted 
to  offspring  to  a  certain  extent.  When  I  dealt  with  this 
correlation  of  direct  adaptation  and  progressive  heredity 
in  1866,  I  laid  special  stress  on  the  "law  of  cumula- 
tive adaptation"  {General  Morphology,  ii.,  p.  208).  "All 
organisms  undergo  important  and  permanent  (chemical, 
morphological,  and  physiological)  changes  when  acted  on 
by  a  change  in  its  life-conditions,  slight  in  itself,  but 
continuing  for  a  long  time  or  being  frequently  repeated." 

368 


THE    EVOLUTION    OF    LIFE 

At  the  same  time  I  pointed  out  that  in  this  case  two 
groups  of  phenomena  are  closely  connected  which  are 
often  separated — namely,  cumulative  heredity:  firstly 
external,  by  the  action  of  the  external  conditions  (food, 
climate,  environment,  etc.),  and  secondly  internal,  by  the 
reaction  of  the  organism,  the  influence  of  internal 
conditions  (habit,  use  and  disuse  of  organs,  etc.).  The 
action  of  outer  influences  (light,  heat,  electricity,  press- 
ure, etc.)  not  only  causes  a  reaction  of  the  organism 
affected  (energy  of  movement,  sensation,  chemosis,  etc.), 
but  it  has  an  especial  effect  as  a  trophic  stimulus  on  its 
nutrition  and  growth.  The  latter  element  has  been 
particularly  studied  by  Wilhelm  Roux;  his  functional 
adaptation  (1881)  coincides  with  my  cumulative  adapta- 
tion, the  close  relation  of  which  to  correlative  adaptation 
I  had  pointed  out  in  1866.  Plate  has  recently  given  this 
"definitely  directed  variation"  the  name  of  ectogenetic 
orthogenesis,  or,  briefly,  ectogenesis. 

The  controversy  about  progressive  heredity  still  con- 
tinues here  and  there.  Weismann  comjjletely  denies  it, 
because  he  cannot  bring  it  into  harmony  with  his  germ- 
plasm  theory,  and  because  he  thinks  there  are  no  experi- 
mental proofs  in  support  of  it.  A  number  of  able 
biologists  agree  with  him,  led  away  by  his  brilliant 
argumentation.  However,  many  of  them  foolishly  lay 
great  stress  on  experiments  in  heredity  which  prove 
nothing;  for  instance,  the  fact  that  the  offspring  of  a 
mammal  that  has  had  its  tail  cut  off  do  not  inherit  the 
feature.  A  number  of  recent  observations  seem  to  prove 
that  in  a  few  cases  even  defects  of  this  sort  (when  they 
have  caused  profound  and  lasting  disease  of  the  part 
affected)  may  be  transmitted  to  offspring.  However,  as 
far  as  the  formation  of  new  species  is  concerned,  the  fact 
is  of  no  consequence;  in  this  it  is  a  question  of  cumula- 
tive or  functional  adaptation.  Experimental  proofs  of 
this  are  difficult  to  find,  if  one  wants  a  strict  demonstra- 
24  369 


THE    WONDERS    OF    LIFE 

tion  of  the  type  of  physical  experiments;  the  biological 
conditions  are  generally  too  complicated  and  offer  too 
many  weak  points  to  rigorous  criticism.  The  beautiful 
experiments  of  Standfuss  and  C.  Fisher  (Zurich)  have 
shown  that  changes  in  the  environment  (such  as  tempera- 
ture or  food)  can  cause  striking  modifications  that 
are  transmitted  to  offspring.  In  any  case,  there  are 
plenty  of  luminous  proofs  of  progressive  heredity  in  the 
vast  arsenal  of  morphology,  comparative  anatomy,  and 
ontogeny. 

Comparative  anatomy  affords  a  number  of  most 
valuable  arguments  for  other  phylogenetic  questions  as 
well  as  progressive  heredity;  and  the  same  may  be  said 
of  comparative  anatomy  and  comparative  ontogeny.  I 
have  collected  and  illustrated  a  good  many  of  these 
proofs  in  the  new  edition  of  my  Anthropogeny.  However, 
in  order  to  understand  and  appreciate  them  aright,  the 
reader  must  have  some  acquaintance  with  the  methods  of 
critical  comparison.  This  means  not  only  an  extensive 
knowledge  of  anatomy,  ontogeny,  and  classification,  but 
also  practice  in  morphological  thinking  and  reasoning. 
Many  of  our  modern  biologists  lack  these  qualifications, 
especially  those  "exact"  observers  who  erroneously 
imagine  they  can  understand  vast  groups  of  phenom- 
ena by  accurate  description  of  detailed  microscopic 
structures,  etc.  Many  distinguished  cytologists,  histol- 
ogists,  and  embryologists  have  completely  lost  the 
larger  view  of  their  work  by  absorption  in  these  details. 
They  even  reject  some  of  the  fundamental  ideas  of  com- 
parative anatomy,  such  as  the  distinction  between 
homology  and  analogy;  Wilhelm  His,  for  instance,  de- 
clared that  these ' '  academic  ideas ' '  are ' '  unreliable  tools . ' ' 
On  the  other  hand,  physiological  experiments  ought  to 
contribute  to  the  solution  of  morphological  problems, 
and  of  these  they  can  say  nothing.  To  show  the  in- 
calculable value  of  comparative  anatomy  for  phylogeny, 

370 


THE    EVOLUTION    OF    LIKE 

I  need  only  point  to  one  of  its  most  successful  depart- 
ments, the  skeleton  of  the  vertebrates,  the  comparison 
of  the  various  forms  of  the  skull,  the  vertebral  column, 
the  limbs,  etc.  It  is  not  in  vain  that  for  more  than  a 
hundred  years  gifted  scientists,  from  Goethe  and  Cuvier 
to  Huxley  and  Gegenbaur,  have  devoted  years  of 
laborious  research  to  the  methodical  comparison  of 
these  similar  yet  dissimilar  forms.  They  have  been 
rewarded  by  the  discovery  of  the  common  laws  of 
structure,  which  can  only  be  explained  in  the  sense  of 
modern  evolution  by  descent  from  common  ancestors. 

We  have  a  striking  example  of  this  in  the  limbs  of 
mammals,  which,  with  the  same  internal  skeletal  struct- 
ure, show  a  very  great  variety  in  outer  form  —  the 
slender  bones  of  the  running  carnivora  and  ungulates, 
the  oar-bones  of  the  whale  and  seal,  the  shovel-bones  of 
the  mole  and  hypudasus,  the  wings  of  the  bat,  the  climb- 
ing bones  of  the  ape,  and  the  differentiated  limbs  of  the 
human  body.  All  these  different  skeletal  forms  have 
descended  from  the  same  common  stem-form  of  the 
oldest  Triassic  mammals;  their  various  forms  and 
structures  are  adapted  in  scores  of  ways  to  different 
functions;  but  they  rise  tJirough  these  functions,  and  all 
these  functional  adaptations  can  only  be  understood  by 
progressive  heredity.  The  theory  of  germ-plasm  gives 
no  causal  explanation  whatever  of  them. 

The  majority  of  recent  biologists  are  of  opinion  that  of 
the  two  chief  constituents  of  the  nucleated  cell  the  cyto- 
plasm of  the  cell-body  discharges  the  function  of  nutri- 
tion and  adaptation,  while  the  caryoplasm  of  the  nucleus 
accomplishes  reproduction  and  heredity.  I  first  advanced 
this  view  in  the  ninth  chapter  of  the  General  Morpltoloiiy 
(in  1866);  and  it  was  afterwards  solidly  and  empirically 
established  by  the  excellent  investigations  of  Eduard 
Strasburger,  the  brothers  Oscar  and  Richard  Hcrtwig, 
and  others.     The  elaborate  finer  structures  which  these 

371 


THE    WONDERS    OF    LIFE 

observers  discovered  in  cell-division  led  to  the  theory 
that  the  colorable  part  of  the  nucleus,  chromatin,  is 
the  real  hereditary  matter,  or  the  material  substratum 
of  the  energy  of  heredity.  Weismann  added  the  theory 
that  this  germ-plasm  lives  quite  separately  from  the 
other  substances  in  the  cell,  and  that  the  latter  (the 
soma-plasm)  cannot  transmit  to  the  germ-plasm  the 
characters  it  has  acquired  by  adaptation.  It  is  on  the 
strength  of  this  theory  that  he  opposes  progressive 
heredity.  The  representatives  of  the  latter  (including 
myself)  do  not  accept  this  absolute  separation  of  germ- 
plasm  from  body-plasm_;  we  believe  that  even  in  the 
process  of  cell-division  in  the  unicellular  organism  there 
is  partial  blending  of  the  two  kinds  of  plasm  (caryolysis) , 
and  that  in  the  multicellular  organism  of  the  histona 
also  the  harmonious  connection  of  all  the  cells  by  their 
plasma-fibres  makes  it  possible  enough  for  all  the  cells 
in  the  body  to  act  on  the  germ-plasm  of  the  germ-cells. 
Max  Kassowitz  has  shown  how  we  can  explain  this 
influence  by  the  molecular  structure  of  the  plasm. 

At  the  beginning  of  the  twentieth  century  a  new  bio- 
logical theory  aroused  a  good  deal  of  interest,  and  was 
welcomed  by  some  as  an  experimental  refutation  of 
Darwin's  theory  of  selection  and  by  others  as  a  valuable 
supplement  to  it.  The  distinguished  botanist  Hugo  de 
Bries  (of  Amsterdam)  gave  an  interesting  lecture  at  the 
scientific  congress  at  Hamburg  in  1901  on  "The  Muta- 
tions and  Mutation-periods  in  the  Origin  of  Species." 
Supported  by  many  years  of  experiments  in  selection 
and  some  ingenious  speculations,  he  thinks  he  has  dis- 
covered a  new  method  of  the  transformation  of  species, 
an  abrupt  modification  of  the  specific  form  at  a  bound, 
and  so  discredited  Darwin's  theory  of  their  gradual 
change  through  long  periods  of  time.  In  a  large  work 
on  Experiments  and  Observations  on  the  Origin  of  Species 
in  the  Plant  Kingdom  (1903),  De  Bries  has  endeavored  to 

372 


THE    EVOLUTION    OF    LIFE 

demonstrate  the  truth  of  his  theory  of  mutation.  The 
warm  approval  which  it  won  from  a  number  of  eminent 
botanists,  and  especially  ve^^etal  physiologists,  was  not 
shared  by  zoologists.  Of  these  Wcismann,  in  his  Lect- 
ures on  the  Theory  of  Descent  (1902,  ii.  p.  358),  and  Plate 
in  his  Problems  of  Species-formation  (1903,  p.  174),  have 
dealt  fully  with  the  theory  of  mutation,  and,  while  ap- 
preciating the  interesting  observations  and  experiments 
of  De  Bries,  have  rejected  the  theory  he  has  built  on 
them.  As  I  share  their  opinion,  I  may  refer  the  reader 
who  is  interested  in  these  difficult  problems  to  their 
works,  and  will  restrict  myself  here  to  the  following 
observations.  The  chief  weakness  of  the  theory  of 
mutation  of  De  Bries  is  on  its  logical  side,  in  his  dog- 
matic distinction  between  species  and  variety,  mutation 
and  variation.  When  he  holds  the  constancy  of  species 
as  a  fundamental  "fact  of  observation,"  we  can  only 
say  that  this  (relative)  permanence  of  species  is  verv 
different  in  the  different  classes.  In  many  classes  (for 
instance,  insects,  birds,  many  orchids  and  graminea) 
we  may  examine  thousands  of  specimens  of  a  species 
without  finding  any  individual  differences;  in  other 
classes  (such  as  sponges,  corals,  in  the  genera  rubus  and 
hieracium)  the  variaVnlity  is  so  great  that  classifiers 
hesitate  to  draw  up  fixed  species.  The  marked  differ- 
ence between  various  forms  of  variability  which  De  Bries 
alleges  cannot  be  carried  through ;  the  fluctuating  varia- 
tions (which  he  takes  to  be  unimportant)  cannot  be 
sharply  distinguished  from  the  abrupt  mutations  (from 
which  new  species  are  supposed  to  result  at  a  bound). 
De  Bries's  mutations  (which  I  distinguished  in  the  Gen- 
eral Morphology  as  "monstrous  changes"  from  other 
kinds  of  variation)  must  not  be  confused  with  the  pale- 
ontological  mutations  of  Waagen  (1S69)  and  Scott 
(1894)  which  have  the  same  name.  The  sudden  and 
striking  changes  of  habit  which  De  Bries  observed  only 

373 


THE    WONDERS    OF    LIFE 

in  one  single  species  of  osnoihera  very  rarely  occur,  and 
cannot  be  regarded  as  common  beginnings  of  the  forma- 
tion of  new  species.  It  is  a  curious  freak  of  chance  that 
this  species  bears  the  name  cEnothera  Lamarckiana;  the 
views  of  the  great  Lamarck  on  the  powerful  influence 
of  functional  adaptation  have  not  been  refuted  by  De 
Bries.  It  must  be  carefully  noted,  in  fact,  that  De  Bries 
is  firmly  convinced  of  the  truth  of  Lamarck's  theory  of 
descent,  like  all  competent  modern  biologists.  This 
must  be  well  understood,  because  recent  metaphysicians 
see  in  the  supposed  refutation  of  Darwinism  the  death 
of  the  whole  theory  of  transformism  and  evolution. 
When  they  appeal  in  this  sense  to  its  most  virulent 
opponents,  Dennert,  Driesch,  and  Fleischmann,  we  may 
remind  them  that  the  curious  sermons  of  these  minor 
sophists  are  no  longer  noticed  by  any  competent  and 
informed  scientist. 

Not  only  in  the  brilliant  speculations  of  De  Bries  and 
Nageli,  but  also  in  many  other  botanical  works  that 
have  lately  attempted  to  advance  the  theory  of  descent, 
we  find  a  striking  difference  from  the  prevailing  views 
of  zoologists  in  the  treatment  of  a  number  of  general 
biological  problems.  This  difference  is,  of  course,  not 
due  to  a  disproportion  of  ability  in  the  two  great  and 
neighboring  camps  of  biology,  but  to  the  differences  in 
the  phenomena  that  we  observe  in  plant  life  on  the  one 
hand  and  animal  life  on  the  other.  It  must  be  noted 
particularly  that  the  organism  of  the  higher  animals 
(including  our  own)  is  much  more  elaborately  differen- 
tiated in  its  various  organs  and  much  more  exposed  to 
our  direct  experience  than  that  of  the  higher  plants. 
The  chief  properties  and  activities  of  our  muscles,  skele- 
ton, nerves,  and  sense-organs,  are  understood  at  once 
in  comparative  anatomy  and  physiology.  The  study 
of  the  corresponding  phenomena  in  the  bodies  of  the 
higher  plants  is  much  more  difficult.     The  features  of 

374 


THE    EVOLUTION    OF    LIFE 

the  innumerable  elementary  organs  in  the  cell-monarchy 
of  the  animal  body  are  much  more  intricate,  yet  at  the 
same  time  much  more  intelligible,  than  those  of  the 
cell-republic  of  the  higher  plant-body.  Thus  the  phylog- 
eny  of  the  plants  encounters  much  greater  dithculties 
than  that  of  the  animals;  the  embryology  of  the  former 
says  much  less  in  detail  than  that  of  the  latter.  We 
can  understand,  therefore,  why  the  biogenetic  law  is  not 
so  generally  recognized  by  botanists  as  by  zoologists. 
Paleontology,  which  provides  such  valuable  fossil  ma- 
terial for  many  groups  of  the  animal  kingdom  that  we 
can  more  or  less  correctly  draw  up  their  ancestral  tree 
on  the  strength  of  this,  gives  us  very  little  for  most 
groups  of  the  plant  kingdom.  On  the  other  hand,  the 
large  and  sharply  demarcated  plant-cell,  with  its  va- 
rious organella,  is  much  more  valuable  in  connection 
with  many  problems  than  the  tiny  animal-cell.  For 
many  physiological  purposes,  in  fact,  the  higher  plant 
body  is  more  accessible  to  exact  physical  and  chemical 
research  than  the  higher  animal  body.  The  antithesis 
is  less  in  the  kingdom  of  the  protists,  as  the  difference 
between  animal  and  vegetal  life  is  mostly  conhned  to 
difference  of  metabolism,  and  finally  disappears  alto- 
gether in  the  province  of  the  unicellular  forms  of  life. 
Hence,  for  a  clear  and  impartial  treatment  of  the  great 
problems  of  biology,  and  especially  of  phylogeny,  it  is 
imperative  to  have  a  knowledge  of  both  zoological  and 
botanical  investigation.  The  two  great  founders  of  the 
theory  of  descent — Lamarck  and  Darwin — were  able  to 
penetrate  so  deeply  into  the  mysteries  of  organic  life 
and  its  development  because  they  had  extensive  attain- 
ments both  in  botany  and  zoology. 

Of  the  various  tendencies  that  have  recently  made 
their  appearance  among  zoologists  and  botanists  in  the 
discussion  of  the  theory  of  descent,  we  frequently  fiml 
Neo-Lamarckism  and  Neo-Darwinism  distinguished  as 

375 


THE    WONDERS    OF    LIFE 

opposing  schools.  This  opposition  has  no  meaning  un- 
less we  understand  by  it  the  alternatives  of  transform- 
ism — with  or  without  the  theory  of  selection.  The  one 
principle  that  distinguishes  Darwinism  proper  from  the 
older  Lamarckism  is  the  struggle  for  existence  and  the 
theory  of  selection  based  on  it.  It  is  quite  wrong  to 
make  the  test  an  acceptance  or  rejection  of  progressive 
heredity.  Darwin  was  just  as  firmly  convinced  as  La- 
marck or  myself  of  the  great  importance  of  the  inheri- 
tance of  acquired  characters,  and  particularly  of  the  in- 
heritance of  functional  adaptations ;  he  merely  ascribed 
to  it  a  more  restricted  sphere  of  influence  than  Lamarck. 
Weismann,  however,  denies  progressive  heredity  alto- 
gether, and  wants  to  trace  everything  to  "the  omnipo- 
tence of  natural  selection."  If  this  view  of  Weismann 
and  the  theory  of  germ-plasm  he  has  based  on  it  are 
correct,  he  alone  has  the  honor  of  founding  a  totally  new 
(and  in  his  opinion  very  fruitful)  form  of  transformism. 
But  it  is  quite  wrong  to  describe  this  Weismannism  as 
Neo-Darwinism,  as  frequently  happens  in  England.  It 
is  just  as  wrong  to  call  Nageli,  De  Bries,  and  other 
modern  biologists  who  reject  selection  Neo-Lamarckists. 
If  the  theory  of  descent  is  right,  as  all  competent 
biologists  now  admit,  it  puts  on  morphology  the  task  of 
assigning  approximately  the  origin  of  each  living  form. 
It  must  endeavor  to  explain  the  actual  organization  of 
each  by  its  past,  and  to  recognize  the  causes  of  its  modi- 
fication in  the  series  of  its  ancestors.  I  made  the  first 
attempt  to  achieve  this  difficult  task  in  founding  stem- 
history  or  phylogeny  as  an  independent  historical  science 
in  my  "General  Evolution"  (in  the  second  volume  of 
the  General  Morphology).  With  it  I  associated  as  a 
second  and  equally  sound  part  ontogeny;  I  understood 
by  this  the  whole  science  of  the  development  of  the 
individual,  both  embryology  and  metamorphology. 
Ontogeny  enjoys  the  privileges  (especially  in  the  way 

376 


T  H  E    EVOLUTION    OF    E  I  F  E 

of  certainty)  of  a  purely  descriptive  science,  when  it 
confines  itself  to  the  faithful  description  of  the  directly 
observed  facts,  either  the  embryonic  processes  in  the 
womb  or  the  later  metamorphic  processes.  The  task  of 
phylogeny  is  much  more  difficult,  as  it  has  to  decipher 
long-past  processes  by  means  of  imperfect  evidence, 
and  has  to  use  its  documents  with  the  utmost  prudence. 

The  three  most  valuable  sources  of  evidence  in 
phylogeny  arc  paleontology,  comparative  anatomy,  and 
ontogeny.  Paleontology  seems  to  be  the  most  reliable 
source,  as  it  gives  us  tangible  facts  in  the  fossils  which 
bear  witness  to  the  succession  of  species  in  the  long 
history  of  organic  life.  Unfortunately,  our  knowledge 
of  the  fossils  is  very  scanty  and  often  very  imperfect. 
Hence  the  numerous  gaps  in  its  positive  evidence  have 
to  be  filled  up  by  the  results  of  two  other  sciences, 
comparative  anatomy  and  ontogeny.  I  have  dealt  fully 
with  this  in  my  AntJiropof^eny.  As  I  have  also  spoken  of 
the  general  features  of  these  phyletic  evidences  in  the 
sixteenth  chapter  of  the  History  of  Creation,  I  need  do 
no  more  here  than  repeat  that  it  is  necessary  to  make 
equal  and  discriminating  use  of  all  three  classes  of 
documents  if  we  are  to  attain  the  aim  of  phylogenv 
correctly.  Unfortunately,  this  necessitates  a  thorough 
knowledge  of  all  three  sciences,  and  this  is  very  rare. 
Most  embr3^ologists  neglect  paleontology,  most  paleon- 
tologists embryology,  while  comparative  anatomy,  the 
most  difficult  part  of  morphology,  involving  most  ex- 
tensive knowledge  and  sound  judgment,  is  neglected 
by  both.  Besides  these  three  sources  of  phylogeny  there 
is  valuable  proof  afforded  by  every  branch  of  biology, 
especially  by  chorology,  oecology,  physiology,  and  bio- 
chemistry. 

Although  there  has  been  very  extensive  phylogenetic 
research  during  the  last  thirty  years,  and  it  has  yielded  a 
number  of  interesting  results,  many  scientists  still  seem 

377 


THE    WONDERS    OF    LIFE 

to  look  on  them  with  a  certain  distrust;  some  contest 
their  scientific  value  altogether,  and  say  that  they  are 
nothing  but  airy  and  untenable  speculations.  This  is 
especially  the  case  with  many  physiologists  who  look 
upon  experiment  as  the  only  exact  method  of  investiga- 
tion, and  many  embryologists  who  think  their  sole  task 
is  description.  In  view  of  these  sceptical  strictures,  we 
may  recall  the  history  and  the  nature  of  geology.  No 
one  now  questions  the  great  importance  and  the  various 
uses  of  this  science,  although  in  it  there  is  no  possibility 
of  directly  observing  the  historical  processes  as  a  rule. 
No  scientist  now  doubts  that  the  three  vast  successive 
formations  of  the  Mesozoic  Period — the  Triassic,  Jurassic, 
and  Cretaceous — have  been  formed  from  sea-deposits 
(lime,  sandstone,  and  clay),  though  no  one  was  a  witness 
to  the  actual  formation;  no  one  doubts  to-day  that  the 
fossil  skeletons  of  fishes  and  reptiles  which  we  find  in 
these  groups  are  not  mysterious  freaks  of  nature,  but  the 
remains  of  extinct  fishes  and  reptiles  that  lived  on  the 
earth  during  those  millions  of  years  long  ago.  And 
when  comparative  anatomy  shows  us  the  genealogical 
connection  of  these  related  forms,  and  phylogeny  (with 
the  aid  of  ontogeny)  constructs  their  ancestral  trees, 
their  historical  hypotheses  are  just  as  sound  and  reliable 
as  those  of  geology ;  the  only  difference  is  that  the  latter 
are  much  simpler,  and  thus  easier  to  construct.  Phylog- 
eny and  geology  are,  in  the  nature  of  the  case,  historical 
sciences. 

Hypotheses  are  necessary  in  phylogeny  and  geolog}^ 
where  the  empirical  evidence  is  incomplete,  as  in  every 
other  historical  science.  It  is  no  detraction  from  the 
value  of  these  to  urge  that  they  are  sometimes  weak  and 
have  to  be  replaced  by  better  and  stronger  ones.  A 
weak  hypothesis  is  always  better  than  none.  We  must, 
therefore,  protest  against  the  foolish  dread  of  hypotheses 
which  is  urged  against  our  phylogenetic  methods  by  the 

37S 


THE    EVOLUTION    OF    LIl^^E 

representatives  of  the  exact  and  descriptive  sciences. 
This  shrinking  from  hypotheses  often  hides  a  defective 
knowledge  of  other  sciences,  an  incapacity  for  synthetic 
thought,  and  a  feeble  sense  of  causality.  The  delusions 
into  which  it  leads  many  scientists  may  be  seen  from  the 
fact  that  chemistry,  for  instance,  is  reckoned  an  "exact" 
science;  yet  no  chemist  has  ever  seen  the  atoms  and 
molecules  of  compounds  with  which  he  is  occupied  daily, 
or  the  complicated  relations  on  the  assumption  of  which 
the  whole  of  modern  structural  chemistry  is  based.  All 
these  hypotheses  rest  on  inferences,  not  on  direct  obser- 
vation. 

I  have,  from  the  first,  insisted  on  the  close  causal 
connection  between  ontogeny  and  phylogeny,  ever  since 
I  distinguished  these  two  parts  of  biogeny  in  the  fifth 
book  of  the  General  Morphology.  I  also  laid  stress  on 
the  mechanical  character  of  these  sciences,  and  en- 
deavored to  give  a  physiological  explanation  of  their 
morphological  phenomena.  Until  then  embryology  had 
been  regarded  as  a  purely  descriptive  science.  Carl 
Ernst  Baer,  who  had  provided  a  solid  foundation  for  it 
in  his  classic  Animal  Embryology  (1828),  was  convinced 
that  all  the  phenomena  of  individual  development  might 
be  reduced  to  the  laws  of  growth;  but  he  was  quite 
unconscious  of  the  real  direction  of  this  growth,  its 
"purposiveness,"  the  real  causes  of  construction.  The 
distinguished  Wiirtzburg  anatomist,  Albert  Kollikcr, 
whose  Manual  of  Htiman  Embryology  (1859)  gave  the 
first  comprehensive  treatment  of  the  science  from  the 
cellular  point  of  view,  adhered,  even  in  the  fourth 
edition  (1884),  to  the  opinion  that  "the  laws  of  the 
development  of  the  organism  are  still  completely  un- 
known." In  opposition  to  this  generally  received 
opinion,  I  endeavored,  in  1866,  to  prove  that  Darwin  had, 
by  his  improvement  of  the  theory  of  descent,  not  only 
solved  the  phylogenetic  problem  of  the  origin  of  species, 

379 


THE    AVONDERS    OF    LIFE 

but,  at  the  same  time,  given  us  the  key  to  open  the 
closed  doors  of  embryology,  and  to  learn  the  causes  of  the 
ontogenetic  processes  as  well.  I  formulated  this  view  in 
the  twentieth  chapter  of  the  General  Morphology,  in 
forty -four  theses,  of  which  I  will  quote  only  the  follow- 
'  ing  three :  i .  The  development  of  organisms  is  a  physio- 
logical process,  depending  on  mechanical  causes,  or 
physico-chemical  movements.  40.  Ontogenesis,  or  the 
development  of  the  organic  individual,  is  directly  de- 
termined by  phylogenesis,  or  the  evolution  of  the  organic 
stem  (phylon)  to  which  it  belongs.  41.  Ontogenesis  is 
a  brief  and  rapid  recapitulation  of  phylogenesis,  deter- 
mined by  the  physiological  functions  of  heredity  and 
adaptation.  The  pith  of  my  biogenetic  principle  is  ex- 
pressed in  these  and  the  remaining  theses  on  the  causal 
nexus  of  biontic  and  phyletic  development.  At  the 
same  time  I  make  it  quite  clear  that  I  reduce  the  physical 
process  of  ontogenesis,  and  also  phylogenesis,  to  a  pure 
mechanics  of  the  plasm  (in  the  sense  of  the  critical 
philosophy) . 

The  comprehensive  fundamental  law  of  organic 
development  was  briefly  formulated  by  me  in  the  fifth 
book  of  the  General  Morphology  and  in  the  tenth  chapter 
of  the  History  of  Creation  (developed  more  fully  in  the 
fourteenth  chapter  of  the  tenth  edition,  1902).  I  after- 
wards sought  to  establish  it  securely  in  two  different 
ways.  In  the  first  place,  I  proved  in  my  Studies  of  the 
Gastrcea  Theory  (18  7 2-1 87  7)  that  in  all  the  tissue-animals, 
from  the  lowest  sponges  and  polyps  to  the  highest 
articulata  and  vertebrates,  the  multicellular  organism 
develops  from  the  same  primitive  embryonic  form  (the 
gastrula),  and  that  this  is  the  ontogenetic  repetition,  in 
virtue  of  heredity,  of  a  corresponding  stem-form  (the 
gastrcEo).  In  the  second  place,  I  made  the  first  attempt 
in  my  Anthropogeny  (1874)  to  illustrate  this  recapitula- 
tion theory  from  the  instance  of  our  own  human  organ- 

380 


THE    EVOLUTION    OF    LIFE 

ism,  by  trying  to  cxpLiin  the  complex  process  of  in- 
dividual develo])mcnt,  for  the  whole  frame  and  every 
single  part  of  it,  by  causal  connection  with  the  stem- 
history  of  our  animal  ancestors.  In  the  latest  edition  of 
this  monistic  "ontogeny  of  man"  I  gave  numbers  of  il- 
lustrations (thirty  plates  and  five  hundred  engravings)  of 
these  intricate  structures,  and  endeavored  to  make  the 
subject  still  plainer  by  the  addition  of  sixty  genetic 
tables.  I  may  refer  the  reader  to  this  work,'  and  not 
dwell  any  further  here  on  the  biogenetic  law,  especially 
as  one  of  my  pui)ils,  lleinrich  Schmidt  (of  Jena),  has 
recently  described  its  biological  significance  and  its 
earlier  history  and  ])resent  position  in  a  very  clear  and 
reliable  little  work  {HaeckeVs  Biogenetic  Law  and  its 
Critics).  I  will  only  add  a  word  or  two  on  the  struggle 
that  has  taken  place  for  thirty  years  over  the  complete 
or  partial  recognition  of  the  biogenetic  law,  its  em- 
pirical establishment,  and  its  philosophic  application. 

In  the  very  name,  "fundamental  law  of  biogeny," 
which  I  have  given  to  my  recapitulation  theory,  I  claim 
that  it  is  universal.  Every  organism,  from  the  uni-l 
cellular  protists  to  the  crytogams  and  ccrlenteria,  and 
from  these  up  to  the  flowering  plants  and  vertebrates, 
reproduces  in  its  individual  development,  in  virtue  of 
certain  hereditary  processes,  a  part  of  its  ancestral  his- 
tory. The  very  word  "recapitulation"  imj)lics  a  partial  ^ 
and  abbreviated  repetition  of  the  course  of  the  original 
phyletic  development,  determined  by  the  "laws  of 
heredity  and  adaptation."  Heredity  brings  about  the 
reproduction  of  certain  evolutionary  features;  adapta- 
tion causes  a  modification  of  them  by  the  conditions  of 
the  environment — a  condensation,  disturbance,  or  falsi- 
fication. Hence  I  insisted  from  the  first  that  the  bio- 
genetic law  consists  of  two  parts,  one  positive  and  palin- 

*  As  already  stated,  it  will  presently  appear  in  England  with 
the  title.  The  Evolution  of  Man. — Trans. 

3S1 


THE    WONDERS    OF    LIFE 

genetic  and  the  other  restrictively  negative  and  ceno- 
genetic.  Palingenesis  reproduces  a  part  of  the  original 
history  of  the  stem;  cenogenesis  disturbs  or  alters  this 
picture  in  consequence  of  subsequent  modifications  of 
the  original  course  of  development.  This  distinction  is 
most  important,  and  cannot  be  too  often  repeated  in 
view  of  the  persistent  misunderstanding  of  my  oppo- 
nents. It  is  overlooked  by  those  who  (like  Plate  and 
Steinmann)  grant  it  only  a  partial  validity,  and  by  those 
who  reject  it  altogether  (like  Keibel  and  Hensen).  The 
embryologist  Keibel  is  the  most  curious  of  these,  as  he 
has  himself  afforded  a  good  many  proofs  of  the  biogenetic 
law  in  his  careful  descriptive-embryological  works.  But 
he  has  so  little  mastered  it  that  he  has  never  under- 
stood the  distinction  between  palingenesis  and  ceno- 
genesis. 

It  is  especially  unfortunate  that  one  of  our  most  dis- 
tinguished embryologists,  Oscar  Hertwig,  of  Berlin,  who 
.provided  a  good  deal  of  evidence  in  favor  of  the  bioge- 
netic law  thirty  years  ago,  has  lately  joined  the  opponents 
of  it.  His  supposed  "correction"  or  modification  of  it 
is,  as  Keibel  has  rightly  said,  a  complete  abandonment 
of  it.  Heinrich  Schmidt  has  partly  explained  the  causes 
of  this  change  in  his  work  on  the  biogenetic  law.  They 
are  not  unconnected  with  the  psychological  metamor- 
phosis which  Oscar  Hertwig  has  undergone  at  Berlin. 
In  the  discourse  on  "The  Development  of  Biology  in 
the  Nineteenth  Century,"  which  he  delivered  at  the  scien- 
tific congress  at  Aachen  in  1900,  he  openly  accepted  the 
duaHst  principles  of  vitalism  (although  he  says  they  are 
"just  as  unreliable  as  the  chemico-physical  conception 
of  the  ODDosinsf  mechanical  school").     The  views  which 

1    J.  o  / 

he  has  latelv  advanced  on  the  worthlessness  of  Darwin- 
ism and  the  unreliability  of  phylogenetic  hypotheses 
are  diametrically  opposed  to  the  opinions  he  represented 
at  Jena  twenty-five  years  ago,  and  to  those  which  his 

382 


THE    EVOLUTION    OF    LIFE 

brother,  Richard  Ilcrtwig,  of  Munich,  has  consistently 
maintained  in  his  admirable  Manual  oj  /ooloi^y. 

In  opposition  to  the  mechanical  ontogeny  which  I 
formulated  in  1866  and  embodied  in  the  biogenetic  law, 
a  number  of  other  tendencies  in  embryology  afterwards 
appeared,  and,  with  the  common  title  of  "mechanical 
embryology,"  branched  out  in  every  direction.  The 
chief  of  these  to  attract  attention  thirty  years  ago  were 
the  pseudo-mechanical  theories  of  Wilhelm  His,  who 
has  rendered  great  service  to  ontogeny  by  his  accurate 
descriptions  and  faithful  illustrations  of  vertebrate- 
embryos,  but  who  has  no  idea  of  comparative  mor])hology, 
and  so  has  framed  the  most  extraordinary  theories  about 
the  nature  of  organic  development.  In  his  Study  of  tlie 
First  Sketch  oj  the  Vertebrate-body  ("1868),  and  many 
later  works,  His  endeavored  to  explain  the  complicated 
ontogenetic  phenomena  on  direct  and  simple  physical 
lines  by  reducing  them  to  elasticity,  bending,  folding 
of  the  embryonic  layers,  etc.,  while  explicitly  rejecting 
the  phylogenetic  method;  he  says  that  this  is  "  a  mere 
by-way,  and  quite  unnecessary  for  the  explanation  of 
the  ontogenetic  facts  (as  direct  consequences  of  physio- 
logical principles  of  development)."  As  a  matter  of 
fact,  nature  rather  plays  the  part  of  an  ingenious  tailor 
in  His's  pseudo-mechanical  and  tectogenetic  speculations, 
as  I  have  shown  in  the  third  chapter  of  the  Anthro- 
pogeny.  Hence  they  have  been  humorously  called  the 
"tailor  theory."  However,  they  misled  a  few  embry- 
ologists  by  opening  the  way  to  a  direct  and  purely  me- 
chanical explanation  of  the  complex  embryonic  phenom- 
ena. Although  they  were  at  first  much  admired,  and 
immediately  afterwards  abandoned,  they  have  found  a 
number  of  supporters  lately  in  various  branches  of  em- 
bryology. 

The  great  success  that  modern  experimental  physiol- 
ogy achieved  by  its  extensive  emplovmcnt  of  ])hvsical 

383 


THE    WONDERS    OF    LIFE 

and  chemical  experiments  inspired  a  hope  of  attaining 
similar  results  in  embryology  by  means  of  the  same 
"exact"  methods.  But  the  application  of  them  in  this 
science  is  only  possible  to  a  slight  extent  on  account  of 
the  great  complexity  of  the  historical  processes  and  the 
impossibility  of  "exactly"  determining  historical  mat- 
ters. This  is  true  of  both  branches  of  evolution,  in- 
dividual and  phyletic.  Experiments  on  the  origin  of 
species  have  very  little  value,  as  I  said  before;  and  this 
is  generally  true  of  embryological  experiments  also. 
However,  the  latter,  especially  careful  experiments  on 
the  first  stages  of  ontogenesis,  have  yielded  some  in- 
teresting results,  particularly  in  regard  to  the  physiology 
and  pathology  of  the  embryo  at  the  earliest  stages  of 
development.  The  Archiv  filr  Entwickelungsmechanik, 
which  is  edited  by  the  chief  representative  of  this  school, 
Wilhelm  Roux,  contains,  besides  these  valuable  inquiries, 
a  good  number  of  ontogenetic  articles,  which  partly  rely 
on  and  partly  ignore  the  biogenetic  law. 

Psychology  and  biogeny  have  been  up  to  the  present 
regarded  as  the  most  difficult  branches  of  biology  for 
monistic  explanation,  and  the  strongest  supports  of 
dualistic  vitalism.  Both  departments  become  accessible 
to  monism  and  a  mechanico-causal  explanation  by  means 
of  the  biogenetic  law.  The  close  correlation  which  it 
establishes  between  individual  and  phyletic  development, 
and  which  depends  on  the  interaction  of  heredity  and 
adaptation,  makes  it  possible  to  explain  both.  In  regard 
to  the  first,  I  formulated  the  following  principle  thirty 
years  ago  in  my  first  study  of  the  gastraea  theory: 
"  Phylogenesis  is  the  mechanical  cause  of  ontogenesis." 
This  single  principle  clearly  expresses  the  essence  of  our 
monistic  conception  of  organic  development: 

In  the  future  every  student  will  have  to  declare  himself  for  or 
against  this  principle,  if  in  biogeny  he  is  not  content  with  a  mere 
admiration  of  the  wonderful  phenomena,  but  desires  to  under- 

384 


THE    EVOLUTION    OF    El  F  E 

stand  their  significance.  The  principle  also  makes  clear  the 
wide  giilf  that  separates  the  older  teleological  and  dualistic 
morphology  from  the  modern  mechanical  and  monistic  science. 
If  the  physiological  functions  of  heredity  and  adaptation  are 
proved  to  be  the  sole  causes  of  organic  construction,  every  kind 
of  teleology,  and  of  dualistic  and  metaphysical  explanation,  is 
excluded  from  the  province  of  hiogeny.  The  irreconcilable 
opposition  between  the  leading  principles  of  the  two  is  clear. 
Either  there  is  or  is  not  a  direct  and  causal  connection  between 
ontogeny  and  phylogeny.  Either  ontogenesis  is  a  brief  com- 
pendium of  phylogenesis  or  it  is  not.  Either  epigenesis  and 
descent — or  pro-formation  and  creation. 

In  repeating  these  principles  here,  I  would  lay  stress 
particularly  on  the  fact  that,  in  my  opinion,  our  "me- 
chanical biogeny"  is  one  of  the  strongest  supports  of 
the  monistic  philosophy. 

3S 


XVII 
THE   VALUE   OF   LIFE 

Changes  of  life — Aim  of  life — Progress  of  life — Historic  aims — 
Historic  waves — Value  of  life  in  classes  and  races  of  men — 
Psychology  of  uncivilized  races — Savages — Barbarians — 
Civilized  nations  —  Educated  nations  —  Three  stages  of 
development  (lower,  middle,  and  higher)  in  each  of  the  four 
classes — Individual  and  social  value  of  civilized  life  in  the 
five  sections  of  nutrition,  reproduction,  movement,  sensa- 
tion, and  mental  life — Estimate  of  human  life. 

THE  value  of  human  life  is  seen  by  us  to-day,  now 
that  evolution  is  established,  in  quite  a  different 
light  from  fifty  years  ago.  We  are  now  accustomed  to 
regard  man  as  a  natural  being,  the  most  highly  developed 
natural  being  that  we  know.  The  same  "eternal  iron 
laws"  that  rule  the  evolution  of  the  whole  cosmos  con- 
trol our  own  life.  Monism  teaches  that  the  universe 
really  deserves  its  name,  and  is  an  all-embracing  unified 
whole — whether  we  call  it  God  or  Nature.  Monistic 
anthropology  has  now  established  the  fact  that  man  is 
but  a  tiny  part  of  this  vast  whole,  a  placental  mammal, 
developed  from  a  branch  of  the  order  of  primates  in  the 
later  Tertiary  Period.  Hence,  before  we  seek  to  estimate 
the  value  of  man's  life,  we  will  cast  a  glance  at  the  sig- 
nificance of  organic  life  generally. 

An  impartial  survey  of  the  history  of  organic  life  on 
our  planet  teaches,  first  of  all,  that  it  is  a  process  of  con- 
stant change.  Millions  of  animals  and  plants  die  every 
second,  while  other  millions  replace  them ;  every  individ- 

386 


THE    VALUE    OF    L  I  F  I^: 

ual  has  his  definite  period  of  Hfe,  whether  it  Hvcs  only 
a  few  hours,  hke  the  one-day  fly  or  the  infusorium,  or, 
Hke  the  Welhngtonia,  the  dragon-tree  of  Orotava,  and 
many  other  giant  trees,  hves  for  thousands  of  years. 
Even  the  species,  the  collection  of  like  individuals,  is 
just  as  transitory,  and  so  are  the  orders  and  classes  that 
embrace  numbers  of  species  of  animals  and  plants.  Most 
species  are  confined  to  a  single  period  of  the  organic 
history  of  the  earth ;  few  species  or  genera  pass  un- 
changed through  several  periods,  and  not  a  single  one 
has  lived  in  all  the  periods.  Phylogeny,  taking  its  stand 
on  the  facts  of  paleontology,  teaches  unequivocally  that 
every  specific  living  form  has  only  existed  a  longer  or 
shorter  period  in  the  course  of  the  many  (more  than  a 
hundred)  million  years  which  make  up  the  history'  of 
organic  life. 

Every  living  being  is  an  end  to  itself.  On  this  point 
all  unprejudiced  thinkers  are  agreed,  whether,  like  the 
teleologist,  they  believe  in  an  entelechy  or  dominant  as 
regulator  of  the  vital  mechanism,  or  whether  they  explain 
the  origin  of  each  special  living  form  mechanically  by 
selection  and  epigenesis.  The  older  anthropistic  idea, 
that  animals  and  plants  were  created  for  man's  use,  and 
that  the  relations  of  organisms  to  each  other  were 
generally  regulated  by  creative  design,  is  no  longer  accept- 
ed in  scientific  circles.  But  it  is  just  as  true  of  the  species 
as  of  the  individual  that  it  lives  for  itself,  and  looks 
above  all  to  self -maintenance.  Its  existence  and  "end" 
are  transitory.  The  progressive  development  of  classes 
and  stems  leads  slowly  but  surely  to  the  formation  of 
new  species.  Every  special  form  of  life — the  individual 
as  well  as  the  species — is  therefore  merely  a  biological 
episode,  a  passing  phenomenal  form  in  the  constant 
change  of  life.  Man  is  no  exception.  "  Nothing  is  con- 
stant but  change,"  said  the  old  maxim. 

The  historical  succession  of  species  and  classes  is,  both 

387 


THE    WONDERS    OF    LIFE 

in  the  animal  and  the  plant  kingdom,  accompanied  by 
a  slow  and  steady  progress  in  organization.  This  is 
directly  and  positively  taught  by  paleontology;  its  crea- 
tion-medals, the  fossils,  are  unequivocal  and  irrefutable 
witnesses  to  this  phylogenetic  advance.  I  have  dealt 
with  the  subject  in  my  History  of  Creation,  and  at  the 
same  time  shown  that  both  the  progressive  improvement 
and  the  increasing  variety  of  the  species  can  be  explained 
mechanically  as  necessary  consequences  of  selection. 
There  was  no  need  of  a  conscious  Creator  or  a  tran- 
scendental purposiveness  to  effect  this.  Scientific  and 
thorough  proof  of  this  will  be  found  in  the  three  volumes 
of  my  Systematic  Phytogeny  (1894).  I  need  only  refer 
briefly  to  the  two  conspicuous  examples  we  have  in  the 
stem-history  of  the  tissue-plants  and  that  of  the  verte- 
brates. Of  the  metaphyta  the  ferns  are  the  chief  groups 
in  the  Paleozoic,  the  gymnosperms  in  the  Mesozoic,  and 
the  angiosperms  in  the  Cenozoic  age.  Of  the  vertebrates 
only  fishes  are  found  in  the  Silurian  age,  dipneusta  only 
begin  in  the  Devonian,  and  the  first  mammals  are  in  the 
Triassic. 

A  number  of  false  teleological  conclusions  have  been 
drawn  from  these  facts  of  progressive  modification  of 
forms,  as  they  are  given  in  paleontology.  The  latest  and 
most  developed  form  of  each  stem  was  taken  to  be  the 
preconceived  aim  of  the  series,  and  its  imperfect  pre- 
decessors were  conceived  as  preparatory  stages  to  the 
attainment  of  this  aim.  It  was  like  the  conduct  of 
many  historians,  who,  when  a  particular  race  or  state 
has  reached  a  high  rank  in  civilization  as  a  result  of  its 
natural  endowments  and  favorable  conditions  of  devel- 
opment, hail  it  as  a  "chosen  people,"  and  regard  its 
imperfect  earlier  condition  as  a  deliberately  conceived 
preparatory  stage.  In  point  of  fact,  these  evolutionary 
stages  were  bound  to  proceed  according  as  the  internal 
structure  (given  by  hereditv)  and  the  outer  conditions 

388 


THE    VALUE    OF    LI  FE 

(provokin.iT  adaptation)  determinc(L  We  cannot  admit 
any  conscious  direction  to  a  certain  end,  either  in  the 
form  of  theistic  predestination  or  pantheistic  fmahty. 
For  this  we  must  substitute  a  simi)le  mechanical  causahty 
in  the  sense  of  psycho-mechanical  monism  or  hylozoism. 

Although  the  stem-history  of  i)lants  and  animals,  like 
the  history  of  humanity,  shows  a  progressive  advance 
taken  as  a  whole,  we  find  a  good  deal  of  vacillation  in 
detail.  These  historical  waves  are  wholly  irregular;  in 
periods  of  decay  the  hollows  of  the  waves  often  persist 
for  a  long  time,  and  are  then  succeeded  by  a  fresh  rise 
to  the  crest  of  another  wave.  New  and  rapidly  advanc- 
ing groups  come  to  take  the  place  of  the  old  decaying 
groups,  bringing  with  them  a  higher  stage  of  organiza- 
tion. Thus,  for  instance,  the  ferns  of  to-day  are  only  a 
feeble  survival  of  the  huge  and  varied  pteridophyta  that 
formed  the  most  conspicuous  part  of  the  paleozoic 
forests  in  the  Devonian  and  Carboniferous  periods ;  they 
were  ousted  in  the  Secondary  Period  by  their  gymno- 
sperm  descendants  (cycadea  and  conifers),  and  these, 
again,  in  the  Tertiary  Period  by  the  angiosperm  flowering 
plants.  So  among  the  terrestrial  reptiles  the  modern 
tortoises,  serpents,  crocodiles,  and  lizards  are  only  a 
feeble  remnant  of  the  enormous  reptile-fauna  that 
dominated  the  Secondary  Period,  the  colossal  dinosauri, 
pterosauri,  ichtyosauri,  and  plesiosauri.  They  were 
replaced  in  the  Tertiary  Period  by  the  smaller  but  more 
powerful  mammals.  In  the  history  of  civilization  the 
Middle  Ages  form  a  deep  valley  between  the  crests  of 
the  waves  of  classical  antiquity  and  modern  culture. 

These  few  examples  suffice  to  show  that  the  various 
classes  and  orders  of  living  things  have  a  very  different 
value  when  comy)ared  with  each  other.  In  regard  to 
their  intrinsic  aim,  self -maintenance,  it  is  true  that  all 
organisms  are  on  a  level,  but  in  their  relations  to  other 
living  things  and  to  nature  as  a  whole  thev  are  of  very 

389 


THE    WONDERS    OF    LIFE 

unequal  value.  Not  only  may  larger  animals  and  plants 
retain  domination  for  a  long  time  in  virtue  of  their 
special  use  or  superior  force  and  mass,  but  small  ones 
may  prevail  owing  to  their  power  of  inflicting  injury 
(bacteria,  fungi,  parasites,  etc.).  In  the  same  way  the 
value  of  the  various  races  and  nations  is  very  unequal 
in  human  history.  A  small  country  like  Greece  has 
almost  dominated  the  mental  life  of  Europe  for  more 
than  two  thousand  years  in  virtue  of  its  superior  culture. 
On  the  other  hand,  the  various  tribes  of  American  Indians 
have,  it  is  true,  developed  a  partial  civilization  in  some 
parts  (Peru  and  Central  America) ;  but,  on  the  whole, 
they  have  proved  incapable  of  advancing. 

Though  the  great  differences  in  the  mental  life  and 
the  civilization  of  the  higher  and  lower  races  are  gener- 
ally known,  they  are,  as  a  rule,  undervalued,  and  so 
the  value  of  life  at  the  different  levels  is  falsely  estimated. 
It  is  civilization  and  the  fuller  development  of  the  mind 
that  makes  civilization  possible,  that  raise  man  so  much 
above  the  other  animals,  even  his  nearest  animal  rel- 
atives, the  mammals.  But  this  is,  as  a  rule,  peculiar 
to  the  higher  races,  and  is  found  only  in  a  very  imperfect 
form  or  not  at  all  among  the  lower.  These  lower  races 
(such  as  the  Veddahs  or  Australian  negroes)  are  psycho- 
logically nearer  to  the  mammals  (apes  or  dogs)  than  to 
civilized  Europeans;  we  must,  therefore,  assign  a  totally 
different  value  to  their  lives.  The  views  on  the  subject 
of  European  nations  which  have  large  colonies  in  the 
tropics,  and  have  been  in  touch  with  the  natives  for 
centuries,  are  very  realistic,  and  quite  different  from  the 
ideas  that  prevail  in  Germany.  Our  idealistic  notions, 
strictly  regulated  by  our  academic  wisdom  and  forced  by 
our  metaphysicians  into  the  system  of  their  abstract 
ideal-man,  do  not  at  all  tally  with  the  facts.  Hence  we 
can  explain  many  of  the  errors  of  the  idealistic  philos- 
ophy  and  many  of   the  practical  mistakes  that  have 

390 


THE    VALUE    OF    LIFE 

been  made  in  the  recently  acquired  German  colonics; 
these  would  have  been  avoided  if  we  had  had  a  better 
knowledge  of  the  low  psychic  life  of  the  natives  (<./.  the 
writings  of  Gobineau  and  Lubbock). 

The  grave  errors  that  have  been  maintained  in 
psychology  for  centuries  are  mostly  due  to  a  neglect  of 
the  comparative  and  genetic  methods  and  the  narrow 
employment  of  self-observation,  or  the  introspective 
method;  they  are  also  partly  due  to  the  fact  that  meta- 
physicians generally  make  their  own  highly  developed 
mind  —  a  scientifically  trained  reason  —  the  starting- 
point  of  their  inquiry,  and  regard  this  as  representative 
of  the  human  mind  in  general,  and  thus  build  up  their 
ideal  scheme.  The  gulf  between  this  thoughtful  mind 
of  civilized  man  and  the  thoughtless  animal  soul  of 
the  savage  is  enormous  —  greater  than  the  gulf  that 
separates  the  latter  from  the  soul  of  the  dog.  Kant 
would  have  avoided  many  of  the  defects  of  his  critical 
philosophy,  and  would  not  have  formulated  some  of  his 
powerful  dogmas  (such  as  the  immortality  of  the  soul,  or 
the  categorical  imperative)  if  he  had  made  a  thorough 
and  comparative  study  of  the  lower  soul  of  the  savage, 
and  phylogenetically  deduced  the  soul  of  civilized  man 
therefrom. 

The  extreme  importance  of  this  comparison  has  only 
been  fully  appreciated  of  late  years  (by  Lubbock, 
Romanes,  etc.).  Fritz  Schultze  (of  Dresden)  made  the 
first  valuable  attempt  in  his  interesting  Psychology  of  the 
Savage  (1900)  to  give  us  an  "evolutionary  psychological 
description  of  the  savage  in  respect  of  intelligence, 
aesthetics,  ethics,  and  religion."  At  the  same  time,  he 
gives  us  "a  history  of  the  natural  creation  of  the  human 
imagination,  will,  and  faith."  The  first  book  of  this 
important  work  deals  with  thought,  the  second  with  will, 
and  the  third  with  the  religious  ideas  of  the  savage,  or 
**  the  stor\'  of  the  natural  evolution  of  religion  "  (fctichism, 

391 


THE    WONDERS    OF    LIFE 

animism,  worship  of  the  heavenly  bodies).  In  an  ap- 
pendix to  the  second  book  the  author  deals  with  the 
difficult  problems  of  evolutionary  ethics,  supporting 
himself  by  the  authority  of  the  great  work  of  Alexander 
Sutherland,  The  Origin  and  Growth  of  the  Moral  Instinct 
(1898).  Sutherland  divides  humanity,  in  regard  to  the 
various  stages  of  civilization  and  mental  development 
(not  according  to  racial  affinity) ,  into  four  great  classes : 
I,  Savages;  2,  barbarians;  3,  civilized  races;  4,  educated 
races.  As  this  classification  of  Sutherland's  not  only 
enables  us  to  take  a  good  survey  of  the  various  forms  of 
mental  development,  but  is  also  very  useful  in  connection 
with  the  question  of  the  value  of  life  at  the  different 
stages,  I  will  briefly  reproduce  the  chief  points  of  his 
characterization  of  the  four  classes. 

I.  Savages. — Their  food  consists  of  wild  natural  prod- 
ucts (the  fruits  and  roots  of  plants,  and  wild  animals 
of  all  kinds).  Most  of  them  are,  therefore,  fishers  or 
hunters.  They  are  ignorant  of  agriculture  and  the 
breeding  of  cattle.  They  live  isolated  lives  in  families 
or  scattered  in  small  groups,  and  have  no  fixed  home. 
The  lowest  and  oldest  savages  come  very  close  to  the 
anthropoid  apes  from  which  they  have  descended,  in 
bodily  structure  and  habits.  We  may  distinguish  three 
orders  in  this  class  —  the  lower,  middle,  and  higher 
savages. 

A.  Lower  savages,  approaching  nearest  to  the  ape, 
pygmies  of  small  stature,  four  to  four  and  a  half  feet 
high  (rarely  four  and  three-quarters) ;  the  women  some- 
times only  three  to  three  and  a  half  feet.  They  are 
woolly  haired  and  flat-nosed,  of  a  black  or  dark  brown 
color,  with  pointed  belly,  thin  and  short  legs.  They 
have  no  homes,  and  live  in  forests  and  caverns,  and 
partly  on  trees;  wander  about  in  small  families  of  ten 
to  forty  persons;  quite  naked,  or  with  just  a  trace  of 
some  primitive  garment.     Of  the  lower  races  now  living 

392 


THE    VA  LUE    OF    1.  1  F  E 

we  must  put  in  this  class  the  Veddahs  of  Ceylon,  the 
Semangs  of  the  Malay  Peninsula,  the  Negritos  of  the 
Philippines,  the  Andaman  Islanders,  the  Kimos  of 
Madagascar,  the  Akkas  of  Guinea,  and  the  Bushmen 
of  South  Africa.  Other  scattered  remnants  of  these 
ancient  negroid  dwarfs,  which  approach  closely  to  the 
anthropoid  apes,  still  live  in  various  parts  of  the  primi- 
tive forests  of  the  Sunda  Islands  (Borneo,  Sumatra, 
Celebes). 

The  value  of  the  life  of  these  lower  savages  is  like  that 
of  the  anthropoid  apes,  or  very  little  higher.  All  recent 
travellers  who  have  carefully  observed  them  in  their 
native  lands,  and  studied  their  bodily  structure  and 
psychic  life,  agree  in  this  opinion.  Compare  the 
thorough  treatment  of  the  Veddahs  of  Ceylon  in  the 
work  of  the  brothers  Sarasin  (of  which  I  have  given  a 
summary  in  my  Travels  in  Ceylon).  Their  only  interests 
are  food  and  reproduction,  in  the  same  simple  form  in 
which  we  find  these  among  the  anthropoid  apes  {cj. 
chapters  xv.  and  xxiii.  of  my  Anthropogeny).  Our  own 
ancestors  were  probably  much  the  same  ten  thousand 
or  more  years  ago.  On  the  strength  of  fossil  remains  of 
Pleistocene  men  Julius  Kollmann  has  shown  it  to  be 
very  probable  that  similar  dwarf  races  (with  an  average 
height  of  four  and  a  half  feet)  inhabited  Europe  at  that 
time. 

B.  Middle  savages,  somewhat  larger  and  less  apelike 
than  the  preceding,  averaging  five  to  five  and  a  half 
feet  in  height.  Their  homes  are  rock  caverns  and 
shelters  from  the  wind  and  rain.  Though  they  have 
shirts  and  other  rudiments  of  clothing,  both  sexes  gen- 
erally go  naked;  they  have  primitive  weapons  of  wood 
and  stone  and  rudely  fashioned  boats,  wander  in  troops 
of  fifty  to  two  hundred,  and  have  no  social  organi- 
zation; certain  races,  however,  have  laws.  To  this 
group  belong  the  Australian  negroes  and  Tasmanians, 

393 


THE    WONDERS    OF    LIFE 

the  Ainos  of  Japan,  the  Hottentots,  Fuegians,  Macas, 
and  some  of  the  forest  races  of  Brazil.  The  value  of 
their  life  is  very  little  superior  to  that  of  the  preceding 
order. 

C.  Higher  savages,  mostly  of  average  human  height 
(smaller  in  colder  regions),  having  always  simple  dwell- 
ings (generally  of  skins  or  the  bark  of  trees).  They 
have  always  primitive  clothing,  and  good  weapons  of 
stone,  bronze,  or  copper.  They  wander  in  troops  of  one 
hundred  to  five  hundred,  led  by  prominent  but  not 
ruling  princes,  and  exhibiting  rudimentary  differences  of 
rank.  The  method  of  life  is  determined  by  hereditary 
customs.  To  this  group  belong  many  of  the  primitive 
inhabitants  of  India  (Todas,  Nagas,  Curumbas,  etc.),  the 
Nicobar  Islanders,  the  Samoyeds,  and  Kamtschadals ; 
in  Africa,  the  negroes  of  Damara;  and  most  of  the 
Indian  tribes  of  North  and  South  America.  Their  life 
is  higher  than  that  of  the  pithecoid  lower  and  middle 
savages,  but  less  than  that  of  the  barbarians. 

11.  Barbarians  or  Semi-savages. — The  greater  part 
of  their  food  consists  of  natural  products,  which  they 
secure  with  some  foresight;  hence  they  have  developed 
agriculture  and  pasture  to  a  greater  or  less  extent.  The 
division  of  labor  is  slight,  each  family  supplying  its  own 
wants.  As  a  rule,  a  stock  of  food  is  provided  for  the 
whole  year.  As  a  result  of  this,  art  begins  to  develop. 
They  have  generally  fixed  dwellings. 

A.  Lower  Barbarians.  Dwellings:  Simple  huts,  gen- 
erally grouped  into  villages  and  surrounded  with  plan- 
tations. Clothing  worn  regularly,  but  very  simple: 
the  men  often  naked  in  hot  climates  or  with  shirt. 
Pottery  and  cooking  utensils,  tools  of  stone,  wood,  or 
bone.  Rudiments  of  commerce  by  exchange.  Groups 
of  one  thousand  to  five  thousand  persons  able  to  form 
larger  communities;  distinctions  of  rank  and  warfare. 
Princes  rule  according  to  traditional  laws.     Of  this  group 

394 


THE    V  A  L  U  E    OV    LIFE 

we  have  in  Asia  many  of  the  aboriginal  inhabitants  of 
India  (Mundas,  Khonds,  Paharias,  Bhecls,  etc.),  the 
Dyaks  of  Borneo,  the  Battaks  of  Sumatra,  Tunguses, 
Kirgises,  etc. ;  in  Africa  the  Kafhrs,  Bcchuanas,  and 
Basutos;  in  Australasia  the  aborigines  of  New  Guinea, 
New  Caledonia,  New  Hebrides,  New  Zealand,  etc. ;  and  in 
America  the  Iroquois  and  Thlinkets,  and  the  inhabitants 
of  Nicaragua  and  Guatemala. 

B.  Middle  barbarians.  Dwellings  good  and  durable, 
generally  of  wood,  roofed  with  cane  or  straw,  forming 
fine  towns.  Clothing  general,  though  nudity  is  not  con- 
sidered immoral.  Pottery,  weaving,  and  metal -work 
pretty  well  developed.  Commerce  in  regular  markets, 
with  the  use  of  money.  States  ruled  by  kings  in  accord- 
ance with  traditional  laws,  fixed  distinctions  of  rank, 
communities  up  to  one  hundred  thousand  persons.  To 
these  belong  in  Asia  the  Calmucks;  in  Africa  many 
negro  races  (Ashantis,  Fantis,  Fellahs,  Shilluks,  Mom- 
buttus,  Owampos,  etc.) ;  in  Polynesia  the  inhabitants  of 
the  Fiji,  Tonga,  Samoa,  and  Markcsas  islands.  In 
Europe  the  Lapps  belonged  to  this  class  two  hundred 
years  ago,  the  ancient  Germans  two  thousand  years  ago, 
the  Romans  before  Numa,  and  the  Greeks  of  the  Homeric 
period. 

C.  Higher  barbarians.  Dwellings,  usually  solid  stone 
buildings.  Clothing  obligatory,  weaving  habitual  occu- 
pation of  the  women,  metal-work  far  advanced,  tools 
generally  of  iron.  Restricted  commerce,  with  minted 
money,  no  rudder-ships.  Crude  judicature  in  fixed 
courts;  rudimentary  writing.  Masses  of  people,  with 
progressive  division  of  labor  and  hereditary  distinctions 
of  rank,  sometimes  reaching  half  a  million  souls,  under 
an  autonomous  ruler.  To  this  class  belong  in  Asia 
most  of  the  Malays  (in  the  large  Sunda  Islands  and  the 
peninsula  of  Malacca),  and  the  nomadic  races  of  Tartars. 
Arabs,   etc.;   in  Polynesia   the  islanders  of  Tahiti  and 

395 


THE    WONDERS    OF    LIFE 

Hawaii;  in  Africa  the  Somalis  and  Abyssinians,  and  the 
inhabitants  of  Zanzibar  and  Madagascar.  Of  the  his- 
toric peoples  of  antiquity  we  have  the  Greeks  of  the 
time  of  Solon,  the  Romans  at  the  beginning  of  the 
republic,  the  Jews  under  the  Judges,  the  Anglo-Saxons 
of  the  Heptarchy,  and  the  Mexicans  and  Peruvians  at 
the  time  of  the  Spanish  invasion. 

III.  Civilized  Races. — Food  and  complex  vital  needs 
are  easily  satisfied  on  account  of  the  advanced  division 
of  labor  and  improvement  of  instruments.  Art  and 
science  are  consequently  developed  more  and  more. 
The  increasing  specialization  brings  about  a  great  elabo- 
ration of  individual  functions,  and  at  the  same  time  a 
great  strengthening  of  the  whole  body  politic,  as  there 
is  complete  mutual  dependence.  The  citizens  see  that 
they  must  submit  to  the  laws  of  the  state. 

A.  Lower  civilized  races.  Towns  with  stone  walls; 
vast  architectural  works  in  stone;  use  of  the  plough  in 
agriculture.  War  is  intrusted  to  a  particular  class. 
Writing  firmly  established,  primitive  law-books,  fixed 
courts.  Literature  begins  to  develop.  To  this  group 
belong  in  Asia  the  inhabitants  of  Thibet,  Bhutan,  Ne- 
paul,  Laos,  Annam,  Korea,  Manchuria,  and  the  settled 
Arabs  and  Turcomans ;  in  Africa  the  Algerians,  Tunisians, 
Moors,  Kabyles,  Tuaregs,  etc.  Of  historical  races  we 
have  the  ancient  Egyptians,  Phoenicians,  Assyrians, 
Babylonians,  Carthaginians,  the  Greeks  after  Marathon, 
the  Romans  of  the  time  of  Hannibal,  and  the  English 
under  the  Norman  kings. 

B.  Middle  civilized  races.  Beautiful  temples  and 
palaces,  built  of  stone  and  brick.  Windows  come  into 
use,  and  sailing-ships.  Commerce  expands.  Writing 
and  written  books  are  general;  the  literary  instruction 
of  the  young  is  attended  to.  Militarism  is  further 
developed;  so  are  legislation  and  advocacy.  Of  these 
we  have  in  Asia  the  Persians,  Afghans,  Birmans,  and 

39^ 


THE    VALU  E    OF     LIFE 

Siamese;  in  Euro])e  the  Finns  and  Magyars  of  the 
eighteenth  century.  Of  historical  peoples  we  must 
count  among  them  the  Greeks  of  the  age  of  Pericles, 
the  Romans  of  the  later  re])ublic,  the  Jews  under  the 
Macedonian  rule,  France  under  the  first  Capets,  and 
England  under  the  Plantagenets. 

C.  Higher  civilized  races.  Stone  houses  general; 
streets  paved ;  chimneys,  canals,  water  and  wind  mills. 
Beginnings  of  scientific  navigation  and  warfare.  Writ- 
ing general,  written  books  widely  distributed,  literature 
esteem.ed.  The  highly  centralized  state  embraces  com- 
munities of  ten  millions  or  more.  Fi.xed  and  written 
codes  of  law  are  officially  promulgated  and  a])plied  by 
courts  to  particular  cases.  Numbers  of  government 
oflficials  have  settled  rank.  To  this  group  belong  in 
Asia  the  Chinese,  Japanese,  and  Hindoos;  also  the  Turks 
and  the  various  republics  of  South  America,  etc.  In 
history  we  have  the  Romans  of  the  empire,  and  the 
Italians,  French,  English,  and  Germans  of  the  fifteenth 
century. 

IV.  Cultivated  R.\ces. — Food  and  other  needs  are 
artificially  supplied  with  the  greatest  ease  and  in  abun- 
dance, human  labor  being  rei3laced  by  natural  forces. 
The  social  organization  grows  and  facilitates  the  play 
of  all  the  social  forces,  and  man  obtains  a  great  freedom 
to  cultivate  his  mental  and  aesthetic  qualities.  Printing 
is  in  general  use,  the  education  of  the  young  one  of 
the  first  duties.  War  becomes  less  important;  rank  and 
fame  depend  less  on  military  bravery  than  on  mental 
superiority.  Legislation  is  influenced  by  representa- 
tives of  the  j)eoj)lc.  Art  and  science  arc  increasingly 
promoted  by  state  aid. 

Alexander  Sutherland  distinguishes  three  stages  of 
development — the  lower,  middle,  and  higher — in  the 
fourth  as  well  as  in  the  preceding  classes.  To  the  first 
stage  he  assigns  "the  leading  nations  of  Eurojie  and 

397 


THE    WONDERS    OF    LIFE 

their  offshoots,  such  as  the  United  States  of  North 
America."  For  the  second  stage — middle  cultured  races 
— he  gives  a  program.me  that  may  be  carried  out  in  three 
or  four  hundred  years'  time,  with  this  definition:  "All 
men  are  well  fed  and  housed;  war  is  universally  con- 
demned, but  breaks  out  now  and  again.  Small  armies 
and  fleets  of  all  the  nations  co-operate  as  a  sort  of  inter- 
national police;  commercial  and  industrial  life  are  di- 
rected according  to  the  moral  precepts  of  sympathy; 
culture  is  general;  crime  and  punishment  rare."  Of 
the  third  and  highest  stage  Sutherland  merely  says, 
"Too  bold  a  subject  for  prophecy,  that  may  not  come 
for  one  thousand  to  two  thousand  years  yet."  This  di- 
vision seems  to  me  too  vague  and  unsatisfactory,  in  the 
sense  that  it  does  not  properly  emphasize  the  civiliza- 
tion of  the  nineteenth  century  in  contrast  with  all  pre- 
ceding stages.  It  would  be  better  to  distinguish  pro- 
visionally the  following  stages  in  modem  civilization: 
first,  sixteenth  to  eighteenth  century;  second,  nine- 
teenth century;  and  third,  twentieth  century  and  the 
future. 

A.  Lower  cultured  races  (Europe,  sixteenth  to  eigh- 
teenth century).  At  the  commencement  of  this  period, 
the  first  half  of  the  sixteenth  century,  we  notice  the 
preparatory  movements  to  the  full  growth  of  mental 
life  which  v/as  to  achieve  such  great  results  in  the  fol- 
lowing periods:  i.  The  cosmic  system  of  Copernicus 
(1543)  maintained  by  Galileo  (1592).  2,  The  discovery 
of  America  by  Columbus  (1492)  and  of  the  East  Indies 
by  Vasco  da  Gama  (1498),  the  first  circumnavigation 
of  the  earth  by  Magellan  (1520)  and  the  evidence  it  af- 
forded of  the  rotundity  of  the  earth.  3.  The  liberation 
of  the  mind  of  Europe  from  the  papal  yoke  by  Martin 
Luther  (15 17)  and  the  repulse  of  the  prevailing  super- 
stition by  the  spread  of  the  Reformation.  4.  The 
new  impulse  to  scientific  investigation  independently  of 

398 


Til  E    VALU  K    ()  F    LI  FE 

scholasticism  and  the  Church  and  of  the  jjhilosophy  of 
Aristotle;  the  founding  of  empirical  science  by  Francis 
Bacon  (1620).  5.  The  spread  of  scientific  knowledge  by 
the  press  (Gutenberg,  1450)  and  wood-engraving.  The 
way  was  prepared  for  modern  civilization  by  these  and 
other  advances  in  the  sixteenth  century,  and  it  quickly 
arose  above  the  barbaric  level  of  the  Middle  Ages.  How- 
ever, it  was  confined  at  first  within  narrow  limits,  as 
the  reactionary  civilization  of  the  Middle  Ages  was  still 
powerful  in  political  and  social  life,  and  the  struggle 
against  superstition  and  unreason  made  slow  progress. 
The  French  Revolution  (1792)  at  last  gave  a  great  im- 
petus in  practical  directions. 

B.  Middle  cultured  races.  This  name  may  be  given 
to  the  leading  nations  of  Eurojje  and  North  America  in 
the  nineteenth  century.  We  may  illustrate  in  the  fol- 
lowing achievements  the  great  advance  which  this  "cen- 
tury of  science"  made  as  compared  with  all  preceding 
ages:  i.  Deepening,  experimental  grounding,  and  gen- 
eral spread  of  a  knowledge  of  nature ;  independent  es- 
tablishment of  many  new  branches  of  science;  founding 
of  the  cell-theory  (1838),  the  law  of  energy  (1845),  and 
the  theory  of  evolution  (1859).  2.  Practical  and  com- 
prehensive application  of  this  theoretical  science  to  all 
branches  of  art  and  industry.  Especially  3.  The  over- 
coming of  time  and  space  by  the  extraordinary  speed  of 
transit  (steamboats,  railways,  telegraphs,  electrotech- 
nics,  4.  Construction  of  the  monistic  and  realistic 
philosophy,  in  opposition  to  the  prevailing  dualistic 
and  mystical  views.  5.  Increasing  influence  of  rational 
scientific  instruction  and  abandonment  of  the  religious 
fiction  of  the  Churches.  6.  Increasing  self-conscious- 
ness of  the  nations  on  account  of  having  a  share  in  gov- 
ernment and  legislation;  extinction  of  the  belief  in  the 
divine  right  of  rulers.  New  distinction  of  classes. 
However,  these  great  advances,  to  which  we  children  of 

399 


THE    WONDERS    OF    LIFE 

the  nineteenth  century  may  point  with  pride,  are  far 
from  being  universal;  they  are  struggUng  daily  with  re- 
actionary views  and  powers  in  Church  and  state,  with 
militarism,  and  with  ancient  and  venerable  immorality 
of  every  kind. 

C.  The  higher  culture  which  we  are  just  beginning  to 
glimpse  will  set  itself  the  task  of  creating  as  happy  and 
contented  a  life  as  possible  for  all  men.  A  perfect  ethic, 
free  from  all  religious  dogma  and  based  on  a  clear  knowl- 
edge of  natural  law,  will  be  found  in  the  golden  rule, 
"Love  thy  neighbor  as  thyself."  Reason  tells  us  that 
a  perfect  state  must  provide  the  greatest  possible  hap- 
piness for  every  individual  that  belongs  to  it.  The  ad- 
justment of  a  rational  balance  between  egoism  and  al- 
truism is  the  aim  of  our  monistic  ethics.  Many  barbaric 
customs  that  are  still  regarded  as  necessary — war,  duel- 
ling, ecclesiastical  power,  etc. — ^will  be  abolished.  Legal 
decisions  will  suffice  to  settle  the  quarrels  of  nations,  as 
they  now  do  of  individuals.  The  chief  interest  of  the 
state  will  be,  not  the  formation  of  as  strong  a  military 
force  as  possible,  but  the  best  possible  instruction  of  its 
young,  with  special  attention  to  art  and  science.  The 
improvement  of  technical  methods,  owing  to  new  dis- 
coveries in  physics  and  chemistry,  will  bring  greater 
satisfaction  of  our  needs  of  life.  The  artificial  produc- 
tion of  albumin  will  provide  plenty  of  food  for  all.  A 
rational  reform  of  the  marriage  relations  will  increase 
the  happiness  of  family  life. 

The  darker  sides  of  modern  life,  of  which  we  are  all 
more  or  less  sensitive,  have  been  laid  bare  by  Max 
Nordau  in  his  Conventional  Lies  of  Civilization.  They 
will  be  greatly  altered  if  reason  is  permitted  to  have  its 
way  in  practical  life,  and  the  present  evil  customs,  based 
on  antiquated  dogmas,  are  suppressed.  But,  in  spite  of 
all  these  shades,  the  luminous  features  of  modern  civili- 
zation are  so  great  that  we  look  to  the  future  with  hope 

400 


THE    VALUE    OF    LIFE 

and  confidence.  We  need  only  glance  Ijack  half  a 
century,  and  compare  life  to-day  with  what  it  was  then, 
in  order  to  realize  the  progress  made.  If  we  regard  the 
modern  state  as  an  elaborate  organism  (a  "social  individ- 
ual of  the  first  order"),  and  compare  its  citizens  to  tlie 
cells  of  a  higher  tissue-animal,  the  difference  between 
the  state  of  to-day  and  the  crudest  family  groups  of 
savages  is  not  less  than  that  between  a  higher  metazoon 
(such  as  a  vertebrate)  and  a  cocnobium  of  protozoa.  The 
progressive  division  of  labor,  on  the  one  hand,  and  the 
centralization  of  society,  on  the  other,  prepare  the  social 
body  for  higher  functions  than  in  isolation,  and  pro- 
portionately increase  the  worth  of  its  life.  To  see  this 
more  clearly,  let  us  compare  the  personal  and  the  social 
value  of  life  in  the  five  chief  fields  of  vital  activity — 
nutrition,  reproduction,  movement,  sensation,  and  men- 
tal life. 

The  first  need  of  the  individual  organism,  self-main- 
tenance, is  met  in  a  much  more  perfect  manner  in  the 
modern  state  than  it  was  formerly.  The  savage  is 
satisfied  with  the  raw  products  of  nature — with  hunting, 
fishing,  and  the  gathering  of  roots  and  fruits.  Agri- 
culture and  pasturage  come  later.  ^Lany  stages  of 
barbarism  and  lower  civilization  must  be  passed  before 
the  conditions  of  feeding,  housing,  and  clothing  provide 
a  secure  and  comfortable  existence  for  man,  and  permit 
the  addition  of  aesthetic  and  intellectual  interests  to  the 
indispensable  search  for  food. 

The  feeding  and  condition  of  the  social  body  as  a 
whole  have  been  improved  by  modem  civilization,  just 
as  in  the  case  of  the  individual.  The  progress  of  chem- 
istry and  agriculture  has  enabled  us  to  produce  food 
in  larger  quantities.  The  ease  and  rapidity  of  transfer 
allow  it  to  be  distributed  over  the  whole  earth.  Scientific 
medicine  and  hygiene  have  discovered  many  means  of 
diminishing  the  dangers  of  disease  and  preventing  its 
a6  401 


THE    WONDERS    OF    LIFE 

occurrence.  By  means  of  public  baths,  gymnasiums, 
popular  restaurants,  public  gardens,  etc.,  greater  care  is 
taken  of  the  health  of  the  communit}^  The  arrangement 
of  modern  houses  and  their  heating  and  lighting  have 
been  immensely  improved.  Modern  social  politics 
strives  more  and  more  to  extend  these  benefits  of  civil- 
ization to  the  lower  classes.  Philanthropic  societies  are 
busy  supplying  the  material  and  spiritual  wants  of  va- 
rious classes  of  sufferers.  It  is  true  there  is  still  a  broad 
margin  for  the  improvement  of  the  national  well-being. 
But,  on  the  whole,  it  cannot  be  denied  that  the  provision 
of  food  in  the  modern  state  is  an  immense  advance  upon 
that  of  the  Middle  Ages  and  of  the  barbaric  period. 

The  great  value  of  modern  civilization  and  its  vast 
progress  beyond  the  condition  of  the  savage  is  seen  in 
no  branch  of  physiology  so  conspicuously  as  in  the 
wonderful  process  of  reproduction  and  the  maintenance 
of  the  species.  In  most  savages  and  barbarians  the  satis- 
faction of  their  powerful  sexual  impulse  is  at  the  same 
low  stage  as  in  the  ape  and  other  mammals.  The  wom- 
an is  merely  an  object  of  lust  to  the  man,  or  even  a  slave 
without  rights,  bought  and  exchanged  like  all  other  prop- 
erty. Improvement  is  slow  and  gradual  in  the  value  of 
this  property,  until  it  reaches  a  high  guarantee  of  per- 
manency in  the  formal  marriage.  The  family  life  proves 
a  source  of  higher  and  finer  enjoyment  for  both  parties. 
The  position  of  woman  advances  with  civilization;  her 
rights  obtain  further  recognition,  and  in  addition  to 
sensual  love  the  psychic  relation  of  man  and  wife  be- 
gins to  develop.  The  common  concern  for  the  proper 
care  and  education  of  the  children,  which  we  find  to  an 
extent  even  in  the  case  of  many  animals,  leads  to  the 
further  development  of  family  life  and  the  founding  of 
the  school.  With  the  advent  of  a  higher  stage  of 
civilization  begins  the  refinement  of  sexual  love,  which 
finds   its   highest   satisfaction,   not  in   the   momentar}^ 

402 


THE    V  A  L  U  E    O  F    L  I  F  E 

gratification  of  the  sex-impulse,  but  in  the  spiritual  rela- 
tion of  the  sexes  and  their  constant  and  intimate  inter- 
course.    The  beautiful  then  unites  with  the  good  and 
the  true  to  form  a  harmonious  trinity.     Hence  love  has 
been   for  thousands   of   years   the   chief   source   of  the 
aesthetic   uplifting   of  man   in   every    respect;   the   arts 
—poetry,  music,  painting,  and  sculpture  — have  drawn 
inexhaustively  from  this  source.     However,  for  the  indi- 
vidual civilized  human  being  this  higher  love  is  of  value, 
not  only  because  it  satisfies  the  natural  and  irresistible 
sex-impulse  in  its  noblest  form,   but  also  because  the 
mutual    influence    of   the    sexes,    their    complementary 
qualities  and  their  common  enjoyment  of  the  highest 
ideal  good,  has  a  great  effect  upon  individual  character. 
A  good  and  happy  marriage — which  is  not  very  common 
to-day — ought  to  be  regarded,  both  psychologically  and 
physiologically,  as  one  of  the  most  important  ends  of 
life  by  every  individual  of  the  higher  nations. 

As  a  pure  marriage  is  the  best  form  of  family  life  and 
the  most  solid  foundation  of  the  state,  its  high  social 
value  is  at  once  evident.  The  attraction  and  mutual 
devotion  of  the  sexes  fulfils  in  the  highest  degree  the 
ethical  golden  rule — the  balance  of  egoism  and  altruism. 
As  Fritz  Schultze  very  truly  says  in  his  Comparative 
Psychology 

We  must  not  seek  the  causes  of  this  altruism  in  the  tran- 
scendental region  of  the  supernatural,  or  in  any  metaphysical 
abstraction,  but  must  go  back  to  the  verv  real  and  natural 
qualities  of  the  organic  being — and  then  there  can  be  no  ques- 
tion that  the  organic  sex-impulse,  at  once  physical  and  j)sycliical 
is  the  first  and  enduring  source  of  all  Invc.  however  sj)iritual,  and 
of  all  real  ethical  and  sympathetic  feehngs  antl  the  morality 
founded  thereon.  There  are  two  primitive  instincts  in  all 
organisms:  that  of  self-maintenance  and  that  of  the  maintenance 
of  the  species.  The  one  is  the  strong  impulse  of  egoism,  the 
other  the  spring  of  altnu'sm:  from  the  one  come  all  unfriendly 
and  from  the  other  all  friendly  feelings.       Every  being  seeks 

403 


THE    WONDERS    OF    LIFE 

first  to  nourish  and  protect  itself  in  virtue  of  its  instinct  of  self- 
maintenance.  But  soon  the  magic  of  the  instinct  for  the  main- 
tenance of  the  species  works  in  it;  it  feels  the  sex-impulse,  and 
thinks  it  is  only  satisfying  its  egoistic  lust  in  yielding  to  it. 
In  this  it  is  wrong;  it  is  not  really  serving  itself,  but  the  whole, 
the  species,  the  genus.  The  ardor  of  love  burns  in  it;  and  how- 
ever sensual  this  love  is  at  first,  the  new  feeling  is  undeniably  a 
feeling  of  belonging  to  another  and  of  mutual  consideration, 
looking  not  only  to  itself,  but  to  another;  not  only  to  its  own 
good,  but  to  that  of  another,  and  finding  its  own  good  only  in 
that  of  the  other.  And  though  this  feeling  at  first  only  unites 
the  two  parents,  it  enlarges  when  children  enter  into  life,  and 
is  extended  to  them  in  the  form  of  parental  love.  Thus,  out  of 
the  sex-impulse  of  the  maintenance  of  the  species,  with  its  strong 
physical  and  psychic  roots,  is  developed  the  love  of  spouses,  of 
parents,  of  children,  and  of  neighbor.  Disinterested  egoism 
goes  even  to  the  extent  of  sacrificing  its  own  life  for  its  young; 
in  this  organic  and  natural  family  love,  and  in  the  sense  of  the 
family  that  comes  of  it,  we  find  the  roots  of  all  sympathetic  and 
really  ethical  altruistic  feelings;  from  this  it  widens  out  to  larger 
spheres.  Hence,  the  family  is  rightly  held  to  be  the  chief  source 
of  all  real  moral  feeling  and  life,  not  only  in  the  human,  but  also 
in  the  animal  world. 


The  further  ennoblement  of  family  life  in  the  advance 
of  civilization  will  give  fresh  proofs  of  the  truth  of  this 
appreciation. 

We  now  turn  to  consider  the  advantages  that  modern 
civilization  offers  in  the  way  of  movement  in  contrast  to 
the  simple  methods  of  locomotion  of  the  savage.  We 
may  point  out  first  that  the  earliest  men,  like  their 
ancestors,  the  anthropoid  apes,  lived  in  trees,  and  only 
gradually  began  to  run  on  the  ground.  Some  of  the 
higher  savages  began  to  use  the  horse  for  riding  and  to 
tame  it.  Many  inhabitants  of  the  coast  or  islands  be- 
gan at  an  early  period  to  make  boats.  Later  the  bar- 
baric tribes  invented  the  wagon,  and  much  later  again 
streets  were  paved  and  vehicles  improved  by  civilized 
races.  But  the  nineteenth  century  brought  the  invalu- 
able means  of  rapid  and  convenient  travelling  by  means 

404 


THE    VALUE    OF    LIFE 

of  steamboats  and  railways.  The  wh(ile  jiroblem  of 
transit  was  revolutionized,  and  in  the  last  few  decades 
further  vast  chanj^es  have  been  made  owing  to  the  ad- 
vance of  electricity.  Modern  ideas  of  time  and  space 
are  quite  different  from  those  of  our  parents  sixty  years 
ago,  or  our  grandparents  ninety  years  ago.  In  our  ex- 
presses we  cover  in  an  hour  a  stretch  of  country  that 
the  mail-coach  took  five  times  and  the  foot-passenger  ten 
times  as  long  to  cover.  As  the  ex])eriments  with  the 
Berlin  electric  railway  have  lately  shown,  we  can  now 
travel  two  hundred  kilometres  in  an  hour.  The  journey 
from  Europe  to  India  now  takes  three  weeks,  whereas  the 
earlier  sailing  -  vessel  took  as  many  months.  The  im- 
mense saving  of  time  that  we  make  is  equivalent  to  a 
lengthening  of  our  own  life.  This  apj^lies  also  to  the 
more  rapid  transit  provided  by  balloons,  automobiles, 
bicycles,  etc.  It  is  easy  to  estimate  the  value  of  these 
improvements;  but  it  is  only  fully  appreciated  by  those 
who  have  lived  long  in  an  uncivilized  country  without 
roads  or  among  savages  whose  legs  are  their  only  means 
of  locomotion. 

This  progress  in  the  means  of  transit  is  not  less 
valuable  socially  than  personally.  If  we  conceive  the 
state  as  a  unified  organism  of  the  higher  order,  the 
development  of  its  means  of  transit  corresponds  in 
many  ways  to  that  of  the  circulation  of  the  blood  in  the 
vertebrate  frame.  The  easy,  rapid,  and  convenient 
transport  of  the  means  of  life  from  the  centre  to  the 
most  distant  parts  of  the  land,  antl  the  corresponding 
development  of  the  net-work  of  railways  and  steamboat 
routes,  are  to  a  certain  extent  direct  tests  of  the  degree 
of  civilization.  To  this  we  must  add  the  creation  of  a 
large  number  of  offices  which  provide  steady  employ- 
ment and  means  of  subsistence  for  many  thousands. 

To  compare  the  complex  sensations  of  civilized  man 
with   the   much  simpler  ones   of  the  savage  ^ve  must 

405 


THE    WONDERS    OF    LIFE 

consider  first  the  functions  of  the  outer  organs  of  sense 
and  then  the  internal  sense-processes  in  the  cortex  of 
the  brain.  Fritz  Schultze  has  pointed  out  in  his  Psy- 
chology of  the  Savage,  in  regard  to  both  sets  of  organs, 
that  the  savage  is  a  man  of  sense-hfe,  the  civihzed 
human  being  a  man  of  mind-Hfe.  When  we  remember 
that  our  higher  psychic  functions  (sensation,  will,  pres- 
entation, and  thought)  are  anatomically  connected 
with  the  phronema  (the  thought-organ  in  the  cortex), 
and  the  inner  sense-perception  with  the  central  sensori- 
um  (in  the  sense-centres  of  the  cortex),  we  shall  expect 
to  find  the  latter  more  developed  in  the  savage  and  the 
former  in  civilized  man.  The  external  sense-action  is 
more  intense  in  quantity,  but  weaker  in  quality,  in  the 
savage  than  in  civilized  man ;  this  is  especially  true  of  the 
finer  and  more  complex  sense-functions  which  we  call 
aesthetic  sensations  and  regard  as  the  source  of  art  and 
poetry.  Most  strongly  developed  of  all  in  the  savage  is 
the  power  of  perceiving  distant  objects  (sight,  hearing, 
smell),  as  they  warn  him  of  the  dangers  about  him.  It 
is  just  the  reverse  with  the  subjective  and  proximate 
feelings  that  are  excited  by  the  immediate  touch  of 
objects  and  are  the  special  instruments  of  sensual  en- 
joyment— taste,  sex-sense,  touch,  and  feeling  of  tempera- 
ture. But  in  both  kinds  of  sense-action  the  civilized 
man  is  far  ahead  of  the  savage  in  respect  of  the  finer 
shades  of  feeling  and  aesthetic  education.  Moreover, 
modern  civilization  has  provided  man  with  various 
means  of  vastly  increasing  and  improving  the  natural 
power  of  his  senses.  We  need  only  mention  the  fields  of 
knowledge  that  have  been  opened  to  us  by  the  microscope 
and  telescope,  the  refined  chemical  methods  of  modern 
cooking,  etc.  The  finer  aesthetic  enjoyment  which  our 
advanced  art  affords — plastic  art  for  the  eye,  music  for 
the  ear,  perfumery  for  the  nose,  cuisine  for  the  tongue — 
is  generally  unintelligible  to  the  savage,  although  he  can 

406 


THE    VALUE    OF    LI  F  E 

see  much  farther,  and  hear  and  smell  much  more 
acutely,  than  civilized  man.  And  in  the  senses  of  near 
objects  (taste,  touch,  temperature)  the  senses  of  the 
savages  are  more  coarse,  and  incapable  of  the  fine 
gradations  of  civilized  man. 

This  more  refined  sense-life  and  the  accompanying 
aesthetic  enjoyment  have  no  less  social  than  personal 
value.  We  have,  in  the  first  place,  the  incalculable 
treasure  of  modern  art  and  science,  their  promotion  by 
the  state,  and  their  embodiment  in  the  training  of  the 
young.  In  the  future  the  higher  races  are  likely  to  give 
more  attention  to  this,  training  the  senses  of  children  as 
well  as  their  intelligence  from  the  earliest  years,  leading 
them  to  a  closer  observation  of  nature  and  reproduction 
of  its  forms  by  drawing  and  painting.  The  art-sense 
must  also  be  fostered  by  the  exhibition  of  models  ami  by 
aesthetic  exercises,  a  larger  place  must  be  given  to  artistic 
education  along  with  the  acquisition  of  real  knowledge, 
and  an  appreciation  of  the  beauties  of  nature  must  be 
created  by  means  of  walks  and  travels.  Then  the 
children  of  civilized  races  will  have  the  inexhaustible 
sources  of  the  finest  and  noblest  pleasures  in  life  opened 
to  them  in  good  time. 

The  higher  psychic  activity  that  civilized  man  calls 
his  "mental  life,"  and  that  is  so  often  regarded  as  a 
kind  of  miracle,  is  merely  a  higher  development  of  the 
psychic  function  we  find  at  a  lower  level  in  the  savage, 
and  is  shared  by  him  with  the  higher  vertebrates.  Com- 
parative psychology  shows  us,  as  I  have  explained  in  the 
seventh  chapter  of  the  Riddle,  the  long  scale  of  develop- 
ment, which  leads  from  the  simple  cell-soul  of  the  protist 
up  to  the  intelligence  of  man.  1  have  already  dealt  in 
various  chapters  with  this  point,  and  need  not  enlarge 
on  it  any  further  to  estimate  the  high  personal  value  of 
mental  life  in  every  civilized  human  being.  It  is  enough 
to  remind  the  reader  of  the  vast  treasures  of  knowledge 

407 


THE    WONDERS    OF    LIFE 

that  lie  open  to  every  one  of  us  at  the  commencement  of 
the  twentieth  century  —  treasures  of  which  our  grand- 
parents at  the  beginning  of  the  last  century  had  not 
the  slightest  presentiment. 

Just  as  the  individual  has  experienced  a  great  advance 
in  the  value  of  his  personal  life  by  the  higher  culture  of 
the  nineteenth  century,  so  the  modern  state  itself  has 
benefited  by  it  in  many  ways.  The  many  discoveries 
made  in  every  branch  of  science  and  technical  industry, 
the  great  advance  in  commerce  and  industrial  life,  in 
art  and  science,  were  bound  to  bring  about  a  higher 
development  of  the  whole  mind  of  a  modern  community. 
Never,  in  the  whole  of  history,  has  true  science  risen  to 
such  an  astounding  height  as  it  has  at  the  beginning  of 
the  twentieth  century.  Never  before  did  the  human 
mind  penetrate  so  deeply  into  the  darkest  mysteries  of 
nature,  never  did  it  rise  so  high  to  a  sense  of  the  unity 
of  nature  and  make  such  practical  use  of  its  knowledge. 
These  brilliant  triumphs  of  modern  civilization  have, 
however,  only  been  made  possible  by  the  various  forces 
co-operating  in  a  vast  division  of  labor,  and  by  the  great 
nations  utilizing  their  resources  zealously  for  the  attain- 
ment of  the  common  end. 

But  we  are  still  far  from  the  attainment  of  the  ideal. 
The  social  organization  of  our  states  is  advanced  only 
on  one  side;  it  is  very  reactionary  on  other  sides.  Un- 
fortunately, the  words  of  Wallace  which  I  quoted  in 
the  Riddle  remain  as  true  as  ever.  Our  modern  states 
will  only  pass  beyond  this  condition  in  the  course  of  the 
twentieth  century  if  they  adopt  pure  reason  as  their 
guide  instead  of  faith  and  traditional  authority,  and  if 
they  come  at  length  to  understand  aright  "man's  place 
in  nature." 

If  we  take  a  summary  view  of  all  that  I  have  said  on 
the  increase  in  the  value  of  human  life  by  the  progress 
of  civilization,  there  can  be  no  doubt  that  both  the 

408 


THE    VALUE    D  F    L  I  F  E 

personal  and  the  social  value  of  life  arc  now  far  higher 
than  they  were  in  the  days  of  our  savage  ancestors. 
Modern  life  is  infinitely  rich  in  the  high  spiritual  interests 
that  attach  to  the  possession  of  advanced  art  and  science. 
We  live  in  peace  and  comfort  in  orderly  social  and  civic 
communities,  which  have  every  care  of  person  and 
property.  Our  personal  life  is  a  hundred  times  finer, 
longer,  and  more  valuable  than  that  of  the  savage, 
because  it  is  a  hundred  times  richer  in  interests,  experi- 
ences, and  pleasures.  It  is  true  that  within  the  limits 
of  civilization  the  differences  in  the  value  of  life  are 
enormous.  The  greater  the  differentiation  of  conditions 
and  classes  in  consequence  of  division  of  labor,  the 
greater  become  the  differences  between  the  educated  and 
uneducated  sections  of  the  community,  and  between 
their  interests  and  needs,  and,  therefore,  the  value  of 
their  lives.  This  difference  is  naturally  most  conspicuous 
if  we  consider  the  leading  minds  and  the  greatest  heights 
of  the  culture  of  the  century,  and  compare  these  with 
the  average  man  and  tlie  masses,  which  wander  far 
below  in  the  vallev,  treading  their  monotonous  and 
weary  way  in  a  more  or  less  stupid  condition. 

The  state  thinks  quite  otherwise  than  the  individual 
man  does  of  the  personal  worth  of  his  life  and  that  of  his 
fellows.  The  modern  state  often  demands  for  its  pro- 
tection the  military  service  of  all  its  citizens.  In  the 
eyes  of  our  ministers  of  justice  the  value  of  life  is  the 
same  whether  there  be  question  of  an  embryo  of  seven 
months  or  a  new-born  child  (still  without  consciousness), 
an  idiot  or  a  genius.  This  difference  between  the  per- 
sonal and  the  social  estimate  of  life  runs  through  the 
whole  of  our  moral  ]:)rinciples.  War  is  still  believed 
by  highly  civilized  nations  to  be  an  unavoidable  evil, 
just  as  barbarians  think  of  individual  murder  or  blood- 
revenge;  yet  the  murder  of  masses  for  which  the  modern 
state  uses  its  greatest  resources  is  in  flagrant  contradic- 

409 


THE    WONDERS    OF    LIFE 

tion  to  the  gentle  doctrine  of  Christian  charity  which  it 
employs  its  priests  to  preach  every  Sunday  with  all 
solemnity. 

The  chief  task  of  the  modern  state  is  to  bring  about 
a  natural  harmony  between  the  social  and  the  personal 
estimate  of  human  life.  For  this  purpose  we  need, 
above  all,  a  thorough  reform  of  education,  the  adminis- 
tration of  justice,  and  the  social  organization.  Only 
then  can  we  get  rid  of  that  mediaeval  barbarism  of  which 
Wallace  speaks ;  to-day  it  finds  expression  triumphantly 
in  our  penal  laws,  our  caste-privileges,  the  scholastic 
nature  of  our  education,  and  the  despotism  of  the 
Church. 

For  each  individual  organism  the  life  of  the  individual 
is  the  first  aim  and  the  standard  of  value.  On  this  rests 
the  universal  struggle  for  self-maintenance,  which  can 
be  reduced  in  the  inorganic  world  to  the  physical  law  of 
inertia.  To  this  subjective  estimate  of  life  is  opposed 
the  objective,  which  proceeds  on  the  value  of  the  indi- 
vidual to  the  outer  world.  This  objective  value  increases 
as  the  organism  develops  and  presses  into  the  general 
stream  of  life.  The  chief  of  these  relations  are  those 
that  come  of  the  division  of  labor  among  individuals 
and  their  association  in  higher  groups.  This  is  equally 
true  of  the  cell-states  which  we  call  tissues  and  persons, 
of  the  higher  stocks  of  plants  and  animals,  and  of  the 
herds  and  communities  of  the  higher  animals  and  men. 
The  more  these  develop  by  progressive  division  of  labor 
and  the  greater  the  mutual  need  of  the  differentiated 
individuals,  so  much  the  higher  rises  the  objective  value 
of  the  life  of  the  latter  for  the  whole,  and  so  much  the 
lower  sinks  the  subjective  value  of  the  individual.  Hence 
arises  a  constant  struggle  between  the  interests  of  in- 
dividuals who  follow  their  special  life-aim  and  those  of 
the  state,  for  which  they  have  no  value  except  as  parts 
of  the  whole. 

410 


XVIII 

MORALITY 

Dualistic  ethics  —  The  catcj^orical  imperative  —  Monistic  ethics 
— Morals  and  adaptation — Variation  and  adaptation  — 
Habit — Chemistry  of  habit — Trcjphic  stimuli — Habit  in 
inorganic  bodies — Instincts — S(jcial  instincts — Instinct  and 
morality — Rij^ht  and  duty — Morals  and  morality — The 
good  and  the  bad — Morals  and  fashions — Sexual  selection — 
Fashion  and  the  feeling  of  shame — Fashion  and  reason — 
Ceremonies  and  cults — Mysteries  and  sacraments — Baptism 
— The  Lord's  Supper — Transubstantiaticni — The  miracle  of 
redemption — Paj^al  sacraments — Marriage — Modern  fash- 
ions— Honor — Phylogeny  of  morals. 

THE  practical  life  of  man  is,  like  that  of  all  the  social 
higher  animals,  ruled  by  impulses  and  customs 
which  we  describe  as  "moral."  The  science  of  morality, 
ethics,  is  regarded  by  the  dualists  as  a  mental  science, 
and  closely  connected  with  religion  on  the  one  hand  and 
psychology  on  the  other.  During  the  nineteenth  century 
this  dualistic  view  retained  its  popularity  especially 
because  the  great  authority  of  Kant,  with  his  dogma  of 
the  categorical  imperative,  seemed  to  have  given  it  a 
solid  foundation,  and  because  it  agreed  admirably  with 
the  teaching  of  the  Church.  Monism,  on  the  other  hand, 
regards  ethics  as  a  natural  science,  and  starts  from  the 
principle  that  morality  is  not  supernatural  in  origin,  buO 
has  been  built  up  by  adaptation  of  the  social  mammals 
to  the  conditions  of  existence,  and  thus  may  be  traced 
eventually  to  physical  laws.     ITcncc  modem  biology  sees 

411 


THE    WONDERS    OF    LIFE 

no  metaphysical  miracle  in  morality,  but  the  action  of 
physiological  functions. 

Our  whole  modern  civilization  clings  to  the  erroneous 
ideas  which  traditional  morality,  founded  on  revelation, 
and  closely  connected  with  ecclesiastical  teaching,  has 
imposed  upon  it.  Christianity  has  taken  over  the  ten 
commandments  from  Judaism,  and  blended  them  with  a 
mystical  Platonism  into  a  towering  structure  of  ethics. 
Kant  especially  lent  support  to  it  in  recent  years  with 
his  Critique  of  Practical  Reason,  and  his  three  central 
dogmas.  The  close  connection  of  these  three  dogmas 
with  each  other,  and  their  positive  influence  on  ethics, 
were  particularly  important  through  Kant  formulating 
the  further  dogma  of  the  categorical  imperative. 

The  great  authority  which  Kant's  dualist  philosophy 
obtained  is  largely  owing  to  the  fact  that  he  subordinated 
pure  reason  to  practical  reason.  The  vague  moral  law 
for  which  Kant  claimed  absolute  universality  is  expressed 
in  his  categorical  imperative  as  follows:  "  So  act  that  the 
maxim  (or  the  subjective  principle  of  your  will)  may  at 
the  same  time  serve  as  a  general  law."  I  have  shown  in 
the  nineteenth  chapter  of  the  Riddle  that  this  categorical 
imperative  is,  like  the  thing  in  itself,  an  outcome  of  dog- 
matic, not  critical,  principles.     As  Schopenhauer  says: 

Kant's  categorical  imperative  is  generally  quoted  in  our  day 
under  the  more  modest  and  convenient  title  of  "the  moral  law." 
The  daily  writers  of  compendiums  think  they  have  founded  the 
science  of  ethics  when  they  appeal  to  this  apparently  innate 
"moral  law,"  and  then  build  on  it  that  wordy  and  confused 
tissue  of  phrases  with  which  they  manage  to  make  the  simplest 
and  clearest  features  of  life  unintelligible,  without  having  ever 
seriously  asked  themselves  whether  there  really  is  any  such 
convenient  code  of  morality  written  in  our  head,  breast,  or 
heart.  This  broad  cushion  is  snatched  from  under  morality 
when  we  prove  that  Kant's  categorical  imperative  of  the 
practical  reason  is  a  wholly  unjustified,  baseless,  and  imaginative 
assumption. 

412 


M  O  R  A  L  I  T  Y 

Kant's  categorical  imperative  is  a  mere  dogma,  and,  like 
his  whole  theory  of  practical  reason,  rests  on  dogmatic 
and  not  critical  grounds.  It  is  a  fiction  of  faith,  and 
directly  opposed  to  the  empirical  principles  of  pure 
reason. 

The  notion  of  duty,  which  the  categorical  nnpcrativc 
represents  as  a  vague  a  priori  law  implanted  in  the 
human  mind — a  kind  of  moral  instinct — can,  as  a  matter 
of  fact,  be  traced  to  a  long  series  of  phyletic  modifications 
of  the  phronema  of  the  cortex.  Duty  is  a  social  sense 
that  has  been  evolved  a  posteriori  as  a  result  of  the  com- 
plicated relations  of  the  egoism  of  individuals  and  the 
altruism  of  the  community.  The  sense  of  duty,  or 
conscience,  is  the  amenability  of  the  will  to  the  feeling 
of  obligation,  which  varies  very  considerably  in  in- 
dividuals. 

A  scientific  study  of  the  moral  law,  on  the  basis  of 
physiology,  evolution,  ethnography,  and  history,  teaches 
us  that  its  precepts  rest  on  biological  grounds,  and  have 
been  developed  in  a  natural  way.  The  whole  of  our 
modern  morality  and  social  and  juridical  order  have 
evolved  in  the  course  of  the  nineteenth  century  out  of 
the  earlier  and  lower  conditions  which  we  now  generally 
regard  as  things  of  the  past.  The  social  morality  of  the 
eighteenth  century  proceeded,  in  its  turn,  from  that  of 
the  seventeenth  and  sixteenth  centuries,  and  still  further 
from  that  of  the  Middle  Ages,  with  its  despotism,  fanat- 
icism, Inquisition,  and  witch  trials.  It  is  equally  clear 
from  modern  ethnography  and  the  comparative  psychol- 
ogy of  races  that  the  morality  of  barbarous  races  has 
been  evolved  gradually  from  the  lower  social  rules  of 
savage  tribes,  and  that  these  differ  only  in  degree,  not 
in  kind,  from  the  instincts  of  the  apes  and  other  social 
vertebrates.  The  comparative  psychology  of  the  verte- 
brates shows,  further,  that  the  social  instincts  of  the 
mammals  and  birds  have  arisen  from  the  lower  stages  of 

413 


THE    WONDERS    OF    LIFE 

the  reptiles  and  amphibia,  and  these  in  turn  from  those 
of  the  fishes  and  the  lowest  vertebrates.  Finally,  the 
phylogeny  of  the  vertebrates  proves  that  this  highly 
developed  stem  has  advanced  through  a  long  series  of 
invertebrate  ancestors  (chordonia,  vermalia,  gastrseada) 
from  the  protists  by  a  process  of  gradual  modification. 
We  find,  even  among  these  unicellulars  (first  protophyta, 
then  protozoa) ,  the  important  principle  which  lies  at  the 
base  of  morality,  association,  or  the  formation  of  com- 
munities. The  adaptation  of  the  united  cell-individuals 
to  each  other  and  to  the  common  environment  is  the 
physiological  foundation  of  the  first  traces  of  morality 
among  the  protists.  All  the  unicellulars  that  abandon 
their  isolated  eremitic  lives,  and  unite  to  form  com- 
munities, are  compelled  to  restrict  their  natural  egoism, 
and  make  concessions  to  altruism  in  the  common  in- 
terest. Even  in  the  globular  ccenobia  of  volvox  and 
magosphaera  the  special  form  and  movement  and  mode 
of  reproduction  are  determined  by  the  compromise  be- 
tween the  egoistic  instincts  of  the  individual  cells  and 
the  altruistic  need  of  the  community. 

Morality,  whether  we  take  it  in  the  narrower  or 
broader  sense,  can  always  be  traced  to  the  physiological 
function  of  adaptation,  which  is  closely  connected 
through  nutrition  with  the  self-maintenance  of  the  or- 
ganism. The  change  in  the  plasm  which  adaptation 
brings  about  is  always  based  on  the  chemical  energy  of 
metabolism  (chapter  ix.).  Hence  it  will  be  as  well  to 
have  a  clear  idea  of  the  nature  of  adaptation.  I  defined 
it  as  follows  in  my  General  Morphology : 

Adaptation  or  variation  is  a  general  physiological  function  of 
organisms,  closely  connected  with  their  radical  function  of 
nutrition.  It  expresses  itself  in  the  fact  that  every  organism 
may  be  modified  by  the  influence  of  the  environment,  and  may 
acquire  characters  which  were  wanting  in  its  ancestors.  The 
causes  of  this  variability  are  chiefly  fotmd  in  a  material  correla- 

414 


M  (J  R  A  L  1  T  V 

lion  between  parts  of  the  orj^^anism  and  the  outer  world.  Varia- 
bility or  adaptability  is  not,  therefore,  a  special  orj^anic  function, 
but    depends    on    the    material,   physico-chemical    process   of 

nutrition. 

I  have  developed  this  conception  of  adaptation  in  the 
tenth  chapter  of  the  History  of  Creation. 

The  nature  of  the  adaptation  and  its  relation  to  varia- 
tion are  often  conceived  in  diflercnt  ways  from  that 
I  have  defined.  Quite  recently  Ludwig  Plate  has  re- 
stricted the  idea,  and  understood  by  adaptation  only 
variations  that  are  useful  to  the  organism.  He  severely 
criticises  my  broader  definition,  and  calls  it  "a  palpable 
error,"  suggesting  that  I  only  retain  it  because  1  am  not 
open  to  conviction.  If  I  wanted  to  return  this  grave 
charge,  I  might  point  to  Plate's  one-sided  and  perverse 
treatment  of  my  biogenetic  law.  Instead  of  doing  this  I 
will  only  observe  that  I  think  the  restriction  of  adapta- 
tion to  useful  variations  is  untenable  and  misleading. 
There  are  in  the  life  of  man  and  of  other  organisms 
thousands  of  habits  and  instincts  that  are  not  useful,  but 
either  indifferent  or  injurious  to  the  organism,  yet  cer- 
tainly come  under  the  head  of  adaptation,  are  main- 
tained by  heredity,  and  modify  the  form.  We  find 
adaptations  of  all  sorts — partly  useful,  partly  indifferent, 
partly  injurious  (the  result  of  education,  training,  dis- 
tortion, etc.) — in  the  life  of  man.  and  the  domestic 
animals  and  plants.  I  need  only  refer  to  the  influence 
of  fashion  and  the  school.  Even  the  origin  of  the  use- 
less (and  often  injurious)  rudimentary  organs  depends  on 
adaptation. 

Habit  is  a  second  nature,  says  an  old  proverb.  This 
is  a  profound  truth,  the  full  ap])reciation  of  which  came 
to  us  through  Lamarck's  theory  of  descent.  The  forma- 
tion of  a  habit  consists  in  the  frequent  repetition  of  one 
physiological  act,  and  so  is  in  j)rinciplc  reducible  to 
cumulative    or    functional    adaptation.     Through    this 

415 


THE    WONDERS    OF    LIFE 

/  frequent  repetition  of  one  and  the  same  act,  which  is 
I  closely  connected  with  the  memory  of  the  plasm,  a 
permanent  modification  is  caused,  either  in  a  positive 
or  a  negative  sense;  positively  the  organ  is  developed 
and  strengthened  by  exercise,  negatively  it  is  atrophied 
or  enfeebled  bv  disuse.  When  this  accumulation  of 
slight  changes  continues,  the  effect  of  adaptation  goes  so 
far  in  time  as  to  produce  new  organs  by  progressive 
modification,  or  to  cause  actual  organs  to  become  useless 
and  rudimentary,  and  finally  disappear,  owing  to  regres- 
sive metamorphosis. 

When  we  make  a  careful  study  of  the  simpler  proc- 
esses of  habit  in  the  lower  organisms,  we  see  that  they 
depend,  like  all  other  adaptations,  on  chemical  changes 
in  the  plasm,  and  that  these  are  provoked  by  trophic 
stimuli — that  is  to  say,  by  external  action  on  the  metab- 
olism. As  Ostwald  rightly  says:  "The  most  impor- 
tant function  of  organisms  is  the  conversion  of  the  va- 
rious chemical  energies  into  each  other.  The  chemical 
energy  that  is  taken  into  the  organism  as  food  is  not 
generally  capable  of  being  applied  directly  to  its  pur- 
poses, but  needs  some  further  preparation.  Every  cell 
is  a  chemical  laboratory,  in  which  the  most  varied  re- 
actions take  place  without  fires  and  retorts.  The  most 
frequently  employed  means  in  this  is  probably  the 
catalytic  acceleration  of  the  usable  and  the  catalytic 
retardation  of  the  useless  reactions.  As  a  proof  of  this 
we  have  the  regular  presence  of  these  enzyma  in  all 
organisms."  In  this  the  greatest  importance  attaches 
to  memory,  which  I  regard  with  Hering  as  a  general 
property  of  living  substance,  "in  virtue  of  which  certain 
processes  in  the  living  being  leave  effects  behind  them 
that  facilitate  the  repetition  of  the  processes."  I  agree 
with  Ostwald  that  "the  importance  of  this  property  can- 
not be  exaggerated.  In  its  more  general  forms  it  effects 
adaptation  and  heredity,  in  its  highest  development  the 

416 


MORA  1.  I  TV 

conscious  memory."  Wliile  the  latter,  and  conscious- 
ness in  general,  reach  the  highest  stage  in  the  mental 
life  of  civilized  man,  the  adaptation  of  the  monera  re- 
mains at  the  lowest  stage.  Among  the  latter  the  bac- 
teria especially,  which  have  assumed  the  most  varied 
and  important  relations  to  other  organisms  in  spite  of 
the  simplicity  of  their  structure,  show  that  this  mani- 
fold adaptation  depends  on  the  formation  of  habits  in 
the  plasm,  and  is  solely  based  on  their  chemical  energy, 
or  their  invisible  molecular  structure.  Once  more  the 
monera  form  a  connecting  link  between  the  organic  and 
inorganic;  they  fill  up  the  deep  gulf,  from  the  point  of 
view  of  energy,  that  seems  to  yawn  between  "  animated  " 
organisms  and  "lifeless"  bodies. 

According  to  the  prevailing  view,  habit  is  a  purely 
biological  process,  but  there  are  processes  even  in  in- 
organic nature  which  come  under  this  head  in  the 
broader  sense.     Ostwald  gives  the  following  illustration: 

If  we  take  two  equal  tubes  of  thin  nitric  acid  and  dis5kDlve  a 
little  metallic  copper  in  one  of  them,  the  li(iuid  will  acquire  the 
power  to  dissolve  a  second  piece  of  the  same  metal  more  (]uick- 
ly  than  the  one  that  remains  unchan.t,'e(l.  The  cause  of  this 
phenomenon — which  inay  be  observed  in  the  same  way  with 
mercury  or  silver  and  nitric  acid-— is  that  the  lower  oxydes  of 
nitrogen  that  are  formed  in  dissolving  the  metal  accelerate  the 
action  of  the  nitric  acid  catalytically  on  the  fresh  metiil.  The 
same  effect  is  produced  if  you  put  part  of  these  oxydes  in  the  acid : 
it  then  acts  much  more  rapidly  than  pure  acid.  The  fonnation 
of  a  habit  consists,  therefore,  in  the  [)roduction  of  a  catalytic 
acceleration  during  the  reaction. 

We  may  not  only  compare  inorganic  habit  with  organic 
adaptation,  which  we  call  habit  or  practice,  but  also 
with  "imitation,"  which  im])lies  a  catalytic  transfer  of 
habits  to  socially  united  living  beings. 

By  instincts  were  formerly  understood,  as  a  rule,  the 
unconscious  impulses  of  animals  which  led  to  purposive 
27  417 


THE    WONDERS    OF    LIFE 

actions,  and  it  was  believed  that  every  species  of  animal 
had  special  instincts  implanted  in  it  by  the  Creator. 
Animals  were  thought,  according  to  Descartes's  view,  to 
be  unconscious  machines  whose  actions  proceed  with 
unvarying  constancy  in  the  particular  form  that  God 
had  ordained.  Although  this  antiquated  theory  of  in- 
stinct is  still  taught  by  many  dualistic  metaphysicians 
and  theologians,  it  has  long  since  been  demolished  by 
the  monistic  theory  of  evolution.  Lamarck  had  observed 
that  most  instincts  are  formed  by  habit  and  adapta- 
tion, and  then  transmitted  by  heredity.  Darwin  and 
Romanes  especially  showed  afterwards  that  these  in- 
herited habits  are  subject  to  the  same  laws  of  variation 
as  other  physiological  functions.  However,  Weismann 
has  recently  taken  great  pains  in  his  Lectures  on  the 
Theory  of  Descent  (xxiii.)  to  refute  this  idea,  and  in  gen- 
eral the  hypothesis  of  an  inheritance  of  acquired  char- 
acters, because  it  will  not  harmonize  with  his  theory  of 
the  germ -plasm.  Ernst  Heinrich  Ziegler,  who  has  re- 
cently (1904)  published  a  subtle  analysis  of  former  and 
present  ideas  of  instinct,  agrees  with  Weismann  that 
"all  instincts  are  due  to  selection,  and  that  they  have 
their  roots  not  in  the  practice  of  the  individual  life,  but 
in  the  variations  of  the  germ."  But  where  else  can  we 
find  the  cause  of  these  "  germ -variations  "  except  in  the 
laws  of  direct  and  indirect  adaptation  ?  In  my  opinion, 
it  is  just  the  reverse;  the  remarkable  phenomena  of  in- 
stinct yield  a  mass  of  evidence  of  progressive  heredity, 
completely  in  the  sense  of  Lamarck  and  Darwin. 

The  great  majority  of  organisms  live  social  lives,  and 
so  are  united  by  the  link  of  common  interests.  Of  all 
the  relations  which  determine  the  existence  of  the 
species,  the  chief  are  those  which  bind  the  individual  to 
other  individuals  of  the  species.  This  is  at  once  clear 
from  the  laws  of  sexual  propagation.  Moreover,  the 
association  of  individuals  is  a  great  advantage  in  the 

418 


M  O  R  A  1>  1  T  Y 

struggle  for  existence.  In  the  case  of  the  higher  ani- 
mals this  association  becomes  particularly  imi)ortant, 
because  it  is  accompanied  by  an  extensive  division  of 
labor.  Then  arises  the  antithesis  of  the  personal  egoism 
and  the  communal  altruism ;  and  in  human  societies  the 
opposition  of  the  two  instincts  is  all  the  greater  when 
reason  recognizes  that  each  has  a  right  to  satisfaction. 
Social  habits  become  moral  habits,  and  their  laws  are 
afterwards  taught  as  sacred  duties,  and  form  the  basis 
of  the  juridical  order. 

The  morals  of  nations,  so  rich  in  psychological  and 
sociological  interest,  are  nothing  more  than  social  in- 
stincts, acquired  by  adaptation,  and  passed  on  from 
generation  to  generation  by  heredity.  An  attempt  has 
been  made  to  distinguish  between  the  two  kinds  of 
habit  by  describing  the  instincts  of  animals  as  constant 
vital  functions  based  on  their  physical  organization, 
and  the  habits  or  morals  of  human  beings  as  mental 
powers  maintained  by  a  spiritual  tradition.  This  dis- 
tinction has,  however,  been  excluded  by  the  modern 
physiological  teaching  that  men's  morals  are,  like  all 
their  other  psychic  ftmctions,  based  physiologically  on 
the  organization  of  their  brain.  The  habits  of  the  in- 
dividual man,  which  have  been  formed  by  adaptation 
to  his  personal  conditions,  become  hereditary  in  his 
family:  and  these  family  usages  can  no  more  be  shar])ly 
distinguished  from  the  general  morals  of  the  community 
than  these  can  be  from  the  precepts  of  the  Church  and 
the  laws  of  the  state. 

When  a  certain  habit  is  regarded  by  all  the  members 
of  a  community  as  important,  its  cultivation  favored 
and  its  breach  punished,  it  is  raised  to  the  position  of 
a  duty.  This  is  true  even  in  the  case  of  the  herds  of 
mammals  (apes,  gregarious  camivora.  and  ungulates) 
and  the  flocks  of  social  birds  (hens,  geese,  ducks).  The 
laws  which  have  been  formed  in  these  cases  by  the  higher 

419 


THE    WONDERS    OF    LIFE 

development  of  social  instincts  are  particularly  striking 
and  equivalent  to  those  of  savage  tribes  when  conspicu- 
ous individuals  (old  or  strong  males)  have  acquired  a 
leadership  of  the  troop,  and  successfully  insure  the  ob- 
servance of  the  proper  habits  or  duties.  Many  of  these 
organized  bands  are  in  some  respects  higher  than  the 
savages  at  the  lowest  stages  who  live  in  isolated  families, 
or  only  form  loose  temporary  associations  of  a  few  fami- 
lies. The  great  progress  made  by  comparative  psychol- 
ogy and  ethnology,  and  historical  and  prehistorical  re- 
search, in  the  second  half  of  the  nineteenth  century, 
confirms  us  in  the  conviction  that  a  long  scale  of  inter- 
mediate stages  joins  the  rudiments  of  law  in  the  social 
primates  and  other  mammals  to  the  sense  of  law  in  the 
lower  savage,  and  this  again  to  that  of  the  barbarian  and 
the  civilized  human  being — right  up  to  the  science  of 
law  in  modern  Europe. 

Like  civil  laws,  the  commands  of  religion  come  origi- 
nally from  the  morals  of  the  savage,  and  eventually  from 
the  social  instincts  of  the  primates.  The  important 
province  of  mental  life  to  which  we  give  the  vague  name 
of  religion  was  developed  at  an  early  stage  among  the 
prehistoric  races  from  whom  we  all  descend.  When  we 
study  its  origin  from  the  point  of  view  of  empirical 
psychology  and  monistic  evolution,  we  find  that  religion 
has  arisen  polyphyletically  from  different  sources — an- 
cestor worship,  the  desire  of  personal  immortality,  the 
craving  for  a  causal  explanation  of  phenomena,  supersti- 
tion of  various  kinds,  the  strengthening  of  the  moral  law 
by  the  authority  of  a  divine  law-giver,  etc.  According  as 
the  imagination  of  the  savage  or  the  barbarian  followed 
one  or  other  of  these  lines  it  raised  up  hundreds  of  relig- 
ious forms.  Only  a  few  of  them  survived  in  the  strug- 
gle for  existence,  and  acquired  (at  least  outwardly)  do- 
j  minion  over  the  modern  mind.  But  as  independent 
and  impartial  science  advances  in  our  time,  religion  is 

420 


M  O  R  A  L  I  T  V 

purified  of  superstition   and   turns  more  and  more  to 
morality. 

The  obedience  to  the  "divine  commands"  wliicli  re- 
ligion demands  of  its  followers  is  often  transferred  by 
human  society  to  rules  that  have  arisen  from  social  cus- 
toms of  subordinate  kinds.  Thus  we  get  the  familiar 
confusion  of  manners  and  morals,  of  conventional  outer 
deportment  and  real  inner  morality.  The  ideas  of  good 
and  bad,  morality  and  immorality,  are  subjected  to 
arbitrary  definitions.  In  this  a  great  part  is  played  by 
the  moral  pressure  which  is  exercised  by  conventional 
ideas  in  the  social  body  on  the  conduct  and  minds  of  its 
members.  However  clearly  and  rationally  the  individ- 
ual thinks  about  the  important  questions  of  practical 
life,  he  has  to  yield  to  the  tyranny  of  traditional  and 
often  quite  irrational  customs.  As  a  matter  of  fact. 
both  in  life  and  in  the  nature  of  the  case  ])ractical  reason 
does  take  that  precedence  of  pure  reason  which  Kant 
claimed. 

The  tyranny  of  custom  in  practical  life  does  not  de- 
pend merely  on  the  authority  of  social  usage,  but  also 
on  the  power  of  selection.  Just  as  natural  selection  in- 
sures the  relative  constancy  of  the  specific  form  in  the 
origin  of  the  animal  and  plant  species,  so  it  has  a  pow- 
erful effect  on  the  origin  of  morals  and  customs.  An  im- 
portant factor  in  this  is  mimetic  adaptation,  or  mimicry, 
the  aping  or  imitating  of  certain  forms  or  fashions  by 
various  classes  of  animals.  This  is  unconscious  in  the 
case  of  many  orders  of  insects,  butterflies,  beetles. 
hvmenoptera,  etc.  When  insects  of  a  certain  family 
come  to  resemble  in  their  outer  form  and  color  and 
design  those  of  another  family,  they  obtain  the  protec- 
tion or  other  advantages  which  these  particular  char- 
acters give  in  the  struggle  for  life.  Darwin.  Wallace. 
Weismann,  Fritz  Miillcr.  Bates,  and  others,  have  shown 
in  numbers  of  instances  how  the  origin  of  these  deceptive 

421 


THE    WONDERS    OF    LIFE 

resemblances  can  be  traced  to  natural  selection,  and  how 
important  they  are  in  the  formation  of  the  species.  But 
many  customs  and  usages  in  human  life  arise  in  just  the 
same  way,  partly  by  conscious  and  partly  by  unconscious 
imitation.  Of  these  the  varying  external  forms  which 
we  call  "fashions"  have  a  most  important  influence  in 
practical  life.  The  phrase  "fashion-ape,"  when  used  in 
a  scientific  sense,  is  not  merely  an  expression  of  con- 
tempt, but  has  also  a  profound  meaning;  it  correctly 
indicates  the  origin  of  fashions  by  imitation,  and  also 
the  peculiar  resemblance  we  find  in  this  respect  between 
man  and  his  cousins,  the  apes.  Sexual  selection  among 
the  primates  has  a  good  deal  to  do  with  this. 

The  great  importance  which  Darwin  ascribes  in  his 
Descent  of  Man  to  the  aesthetic  selection  of  the  respective 
sexes  is  equally  true  of  man  and  of  all  the  higher  verte- 
brates that  have  a  feeling  of  beauty,  especially  the 
amniotes  (mammals,  birds,  and  reptiles).  The  beauti- 
ful coloring  and  marking  and  ornamentation  which  dis- 
tinguish the  males  from  the  females  are  due  entirely 
to  the  careful  individual  selection  of  the  former  by  the 
latter.  Thus  the  various  kinds  of  ornamental  hair 
(beard,  hair  of  head,  etc.),  the  tint  of  the  face,  the 
peculiar  form  of  the  lips,  nose,  ears,  etc.,  are  to  be  ex- 
plained, as  we  find  them  in  man  and  the  male  ape; 
also  the  brilliant  plumage  of  the  humming-bird,  the 
bird  of  paradise,  pheasant,  etc.  I  have  dealt  fully  with 
these  interesting  facts  in  the  eleventh  chapter  of  the 
History  of  Creation,  and  must  refer  the  reader  thereto. 
I  will  only  point  out  here  how  valuable  the  whole  of 
this  chapter  of  Darwinism  is  for  the  understanding  of 
the  foundation  of  species  on  the  one  hand  and  men's 
fashions  and  customs  on  the  other.  It  is  most  closely 
connected  with  ethical  problems. 

The  growth  of  fashion  in  civilized  life  is  very  impor- 
tant, not  only  for  the  development  of  the  sense  of  beauty 

423 


M  O  R  A  L  T  T  ^' 

and  for  the  sexual  selection  of  the  sexes,  hut  also  in  con- 
nection with  the  origin  of  the  feeling  of  shame  and  the 
finer  psychological  traits  that  relate  to  it.  The  lower 
savages  have  no  more  sense  of  shame  than  animals  or 
children.  They  are  quite  naked,  and  accomplish  the 
sexual  act  without  the  slightest  trace  of  shame.  The 
beginning  of  clothing  which  we  find  among  the  middle 
savages  is  not  due  to  a  sense  of  shame,  but  partly  to  low 
temperature  (in  the  polar  regions),  partly  to  vanity  and 
love  of  decoration  (such  as  ornamenting  the  ears,  lips, 
nose,  and  sex-organs  by  the  insertion  of  shells,  pieces 
of  wood,  flowers,  stones,  etc.).  Afterwards  the  sense  of 
shame  sets  in,  and  we  have  the  covering  of  certain  parts 
of  the  body  with  leaves,  girdles,  shirts,  etc.  In  most 
nations  the  sexual  parts  are  the  first  to  be  covered ; 
though  some  attach  importance  to  the  veiling  of  the 
face.  In  many  Oriental  tribes  (especially  Mohamme- 
dan) it  is  still  the  first  precept  of  female  chastity  to  veil 
the  face  (the  most  characteristic  part  of  the  indiviiiual), 
while  the  rest  of  the  body  may  remain  naked.  General- 
ly speaking,  the  aesthetic  and  psychological  relations  of 
the  sexes  play  the  chief  part  in  the  higher  development 
of  morals.  Morality  is  often  taken  to  be  synonymous 
with  the  law  of  sexual  intercourse. 

As  the  features  of  civilized  life  advance,  the  influence 
of  reason  increases,  and  so  does  the  power  of  hereditary 
tradition  and  the  moral  ideas  associated  with  it.  The 
result  is  a  severe  conflict  between  the  two.  Reason 
seeks  to  judge  everything  by  its  own  standard,  to  learn 
the  causes  of  phenomena  and  direct  practical  life  accord- 
ingly. On  the  other  hand  tradition,  or  "good  morals." 
looks  at  everything  from  the  point  of  view  of  our  fore- 
fathers and  other  venerable  laws  and  religious  precepts. 
It  is  indifferent  to  the  independent  discoveries  of  reason 
and  the  real  causes  of  things.  It  demands  that  the 
practical  life  of  every  individual  be  framed  in  accordance 

4-^3 


THE    WONDERS    OF    LIFE 

with  the  hereditary  morality  of  the  race  or  state.  Thus 
we  get  the  inevitable  conflict  between  reason  and  tra- 
dition, or  science  and  religion,  which  continues  in  our 
own  day.  Sometimes  in  the  course  of  it  a  "new  fash- 
ion" is  substituted  for  some  sacred  tradition,  a  transi- 
tory custom  that  succeeds  in  imposing  itself  by  its 
noyelty  or  curiosity;  and  when  this  has  contrived  to 
win  general  acceptance,  or  has  gained  the  support  of 
Church  or  state  to  some  extent,  it  is  regarded  in  much 
the  same  light  as  the  older  morality. 

The  lowest  races  of  the  present  time  (for  instance, 
the  pithecoid  pygmies,  the  Veddahs  of  Ceylon,  the  Ak- 
kas  of  Central  Africa)  are  very  little  higher  than  their 
primate  ancestors  in  mental  development.  This  is  also 
true  of  their  habits  of  life  and  morals.  As  their  ideas 
are  for  the  most  part  concrete  and  sensual,  their  power 
of  forming  abstract  concepts  is  very  little  developed; 
they  have  hardly  any  religious  ideas  to  speak  of.  But 
with  the  middle  savages  we  begin  to  find  the  craving  to 
know  the  causes  of  things  and  the  idea  of  spirits  that  are 
concealed  behind  the  phenomena  of  sense.  Dread  of 
these  leads  to  worship,  fetichism,  and  animism,  the  be- 
ginning of  religion.  Even  at  this  early  stage  of  worship 
we  find  certain  customs  associated  with  the  cult  to 
which  a  symbolical  or  mysterious  meaning  is  given. 
These  ceremonies  lead  on  in  the  higher  races  to  the 
great  religious  festivities,  which  the  Greeks  called  "mys- 
teries." Sensual  images  of  various  kinds  are  mixed  up 
in  them  with  supersensual  ideas  and  superstitions.  The 
festivals,  processions,  dances,  hymns,  and  sacrifices  of 
all  sorts  that  form  part  of  the  cult  are  more  or  less  con- 
cerned with  the  mysterious,  and  are  therefore  considered 
"holy."  They  are  often  made  the  pretext  of  sensual 
gratifications,  which  end  in  gross  immorality  and  orgies. 

From  the  older  pagan  and  Jewish  religious  usages 
were  afterwards  developed  in  the  Christian  Church  those 

424 


M  ( )  R  A  L  I  T  Y 

parts  of  the  cult  which  arc  known  as  sacraments.  These 
miraculous  sacraments,  by  the  mysterious  action  of 
which  man  is  supposed  to  be  born  a^^ain  or  rcj^'cncrated, 
very  quickly  became  powerful  instruments  in  the  hand 
of  the  Church  and  thorny  problems  for  theologians,  es- 
pecially after  Gregory  the  Great  introduced  the  dogmas 
of  Purgatory  and  the  relieving  power  of  the  Mass.  Ac- 
cording to  St.  Thomas  of  Aquin,  the  sacraments  are 
channels  that  convey  the  grace  of  God  to  sinful  man. 
The  papal  authorities  fixed  their  number  at  seven  (bap- 
tism, eucharist,  penance,  confirmation,  matrimony,  or- 
ders, and  extreme  unction)  in  the  twelfth  century.  The 
superstitious  content  of  these  sacraments  was  generally 
lost  sight  of  in  the  glamour  of  their  ceremonious  side,  but 
their  authority  was  unshaken.  Since  the  Reformation 
the  Protestants  have  retained  only  the  two  chief  sacra- 
ments which  were  founded  by  Christ  himself — Baptism 
and  the  Lord's  Supper. 

Christian  baptism  is  a  continuation  of  the  older  ceremonies  of 
washing  and  purification  that  were  in  use  thousands  of  years 
before  Christ  amone^  nations  of  the  East  and  amonj^  the  Greeks. 
They  combined  the  hygienic  value  of  the  bath  with  the  idea  of  a 
regeneration  of  the  soul  and  spiritual  purification.  Au^istine, 
who  founded  the  dogma  of  original  sin.  held  that  the  baptism 
of  children  was  necessary  for  the  salvation  of  their  souls,  and  it 
then  became  general.  It  has  since  given  rise  to  a  number  of 
superstitious  ideas  and  unfortunate  family  troubles,  but  it  is 
still  regarded  as  a  sacred  ceremony.  Millions  of  Christians  still 
believe  that  the  child's  soul  is  saved  (though  it  has  no  conscious- 
ness whatever  when  baptized)  and  delivered  from  the  power  of 
the  devil  and  the  curse  of  sin  by  baf)tism. 

The  second  sacrament  that  Luther  retained  is  the  Lord's 
Supper,  or  the  sacrament  of  the  body  and  blood  of  Christ.  It 
was  instituted  by  Christ  r)n  the  night  before  his  death,  and  is  a 
continuation  of  the  paschal  sujiper  of  the  Jews,  in  wljich  the 
head  of  the  house  shared  bread  and  wine  with  his  family  with 
certain  ritual  ceremonies.  In  this  paschal  supper  the  people  of 
Israel  celebrated  their  release  from  the  Ixindage  of  Egpyt  and 
their  distinction  as  the  "chosen  people."     By  connecting  his 


THE    WONDERS    OF    LIFE 

"last  supper"  with  the  traditional  rite  of  the  Jews,  Christ  sought 
/  on  the  one  hand  to  found  the  new  dispensation  on  the  old,  and 
on  the  other  hand  to  institute  a  love-feast  (communion  or  agape) 
among  his  followers.  Like  baptism,  the  Lord's  Supper  led 
afterwards  to  the  bitterest  controversy  among  theologians. 

The  differences  of  opinion  as  to  the  Eucharist  in  the  Middle 
Ages  culminated  at  last  in  the  opposition  of  the  two  reformers, 
Luther  and  Zwingli.  The  latter,  the  founder  of  the  Free  Re- 
formed Church,  saw  in  the  Supper  only  a  symbolical  act  and  a 
commemoration  of  Christ.  Luther,  however,  adhered  to  the 
mysterious  miracle  that  had  been  defined  in  12 15  by  the  dogma 
of  transubstantiation.  Bread  and  wine  are  believed  on  this 
view  to  be  converted  physically  into  the  body  and  blood  of 
Christ!  I  was  taught  this  in  1848  by  the  minister  who  prepared 
me  for  confirmation,  and  to  whom  I  was  greatly  attached.  We 
were  actually  to  perceive  this  change  when  we  assisted  at  the 
Supper  for  the  first  time,  if  we  did  so  with  real  faith.  As  I  was 
quite  conscious  of  having  this  quality,  I  had  great  expectations 
of  the  miracle.  But  I  was  very  painfully  disillusioned  when  I 
found  only  the  familiar  taste  of  bread  and  wine,  not  the  flesh  and 
blood  that  faith  had  desired.  I  had  to  regard  myself  (then  a 
boy  of  fourteen  years)  as  an  utterly  abandoned  sinner,  and  it 
was  with  the  greatest  difficulty  that  my  parents  succeeded  in 
pacifying  me  over  my  want  of  faith. 

I  have  spoken  somewhat  fully  in  the  seventeenth  chapter  of 
the  Riddle  of  the  view  of  the  papacy  and  ultramontanism  which 
modem  historical  and  anthropological  science  leads  us  to  form. 
No  one  who  has  any  idea  of  history  and  of  the  metamorphoses  of 
religion  can  question  that  Romanism  is  a  miserable  caricature  of 
primitive  Christianity;  it  retains  the  name,  but  has  completely 
reversed  the  principles.  In  the  course  of  its  domination,  from 
the  fourth  to  the  sixteenth  century,  the  papacy  has  raised  up  the 
marvellous  structure  of  the  Catholic  hierarchy,  but  has  departed 
farther  and  farther  from  the  stand-point  of  pure  Christianity, 
The  aim  of  Romanism  is  to-day,  as  it  was  a  thousand  years  ago, 
to  dominate  and  exploit  a  blindly  believing  humanity.  It 
finds  admirable  instruments  for  this  in  its  mystic  sacraments,  to 
which  it  has  ascribed  an  "indelible  character."  From  the  cradle 
to  the  grave,  from  baptism  to  the  last  anointing,  in  confirmation 
and  penance,  the  believer  must  be  reminded  that  he  must  live 
as  an  obedient  and  self-sacrificing  child;  and  the  sacrament  of 
ordination  must  teach  him  that  the  priest,  with  his  higher 
inspiration,  is  the  only  intermediary  between  man  and  God. 
The  symbolical  rites  that  are  associated  with  these  sacraments 

426 


iM  O  R  A  1.  I  T  Y 

serve  to  surround  Iheni  with  the  ma^^ic  of  the  mysterious  and 
exclude  the  penetration  of  reason.     This  is  particularly  true  of 

the  sacrament  that  has  had  the  jjreatcst  practical  inllucnce — 

matrimony. 

In  view  of  the  extreme  importance  of  the  hfe  of  the 
family  as  a  foundation  of  social  and  civic  life,  it  is  ad- 
visable to  consider  marriage  from  the  biological  point 
of  view,  as  an  orderly  method  of  reproduction.  Here, 
as  in  all  other  sociological  and  psychological  questions, 
we  must  be  careful  not  to  accept  the  present  features  of 
civilized  life  as  a  general  standard  of  judgment.  We 
have  to  take  a  comparative  view  of  its  various  stages, 
as  we  find  them  among  barbarians  and  savages.  When 
we  do  this  impartially,  we  see  at  once  that  reproduction, 
as  a  purely  physiological  process  having  for  its  end  the 
maintenance  of  the  species,  takes  place  in  just  the  same 
way  among  uncultivated  races  as  among  the  anthropoid 
apes.  We  may  even  say  that  many  of  the  higher  ani- 
mals, especially  monogamous  mammals  and  birds,  have 
reached  a  higher  stage  than  the  lower  savages;  the  ten- 
der relations  of  the  two  sexes  towards  each  other,  their 
common  care  of  their  young,  and  their  family  life,  have 
led  to  the  development  of  higher  sexual  and  domestic 
instincts,  to  which  we  may  fitly  ascribe  a  moral  char- 
acter. Wilhelm  Bolsche  has  shown,  in  his  Life  of  Love 
in  Nature,  how  a  long  series  of  remarkable  customs  has 
been  developed  in  the  animal  world  by  adaptation  to 
various  forms  of  reproduction.  WVstermarck  has  point- 
ed out,  in  his  History  of  Marriai^e,  how  the  crude  animal 
forms  of  marriage  current  among  savages  have  been 
gradually  elevated  as  we  rise  to  higher  races.  As  the 
sensual  pleasure  of  generation  is  combined  with  the 
finer  psychological  feeling  of  sympathy  and  psychic  at- 
tachment, the  latter  gains  constantly  on  the  former,  and 
this  refined  love  becomes  one  of  the  richest  sources  of 
the  higher  spiritual  functions,  especially  in  art  and  po- 

427 


THE    WONDER  vS    OF    LIFE 

etry.  Marriage  itself,  of  course,  remains  a  physiological 
act,  a  wonder  of  life,  with  the  organic  sex  impulse  as  its 
chief  foundation.  As  the  conclusion  of  marriage  repre- 
sents one  of  the  most  important  moments  in  human  life, 
we  find  it  accompanied  by  symbolic  ceremonies  and 
festive  rites  even  among  lower  tribes.  The  immense 
variety  of  marriage  festivals  shows  how  this  important 
act  has  appealed  to  the  imagination.  Priests  quickly 
recognized  this,  and  decked  out  marriage  with  all  kinds  of 
ceremonies  and  turned  it  to  the  advantage  of  their 
Church.  While  the  Catholic  Church  raised  it  to  the 
status  of  a  sacrament  and  ascribed  to  it  an  "indelible" 
character,  it  declared  that  it  was  indissoluble  when 
performed  according  to  ecclesiastical  rite.  This  un- 
wholesome influence  of  Romanism,  this  dependence  of 
matrimony  on  religious  mysteries  and  ceremonies,  and 
difficulty  of  obtaining  divorce,  etc.,  still  continue  in  our 
day.  It  is  only  a  short  time  since  the  German  Reichstag, 
under  the  influence  of  the  Centre  [Catholic]  party,  added 
laws  to  its  civic  code  which  increase  instead  of  lessening 
the  difficulty  of  obtaining  divorce.  Reason  demands 
the  liberation  of  marriage  from  ecclesiastical  pressure. 
It  demands  that  matrimony  be  grounded  on  mutual 
love,  esteem,  and  devotion,  and  that  it  at  the  same 
time  be  counted  a  social  contract,  and  be  protected,  as 
civil  marriage,  by  proper  legislation.  But  when  the 
contracting  parties  find  (as  so  often  happens)  that  they 
have  mistaken  each  other's  character,  and  that  they  do 
not  suit  each  other,  they  should  be  free  to  dissolve  the 
bond.  The  pressure  which  comes  of  marriage  being  re- 
garded as  a  sacrament,  and  which  prevents  the  dissolu- 
tion of  unhappy  marriages,  is  merely  a  source  of  vice 
and  crime. 

We  find  in  many  other  features  of  our  social  life, 
besides  marriage,  a  contradiction  between  the  demands 
of  reason  and  the  traditional  usages  which  nioderr^  civ- 

428 


M  ()  R  A  L  I  T  V 

ilization  has  taken  over  as  a  hcritaKc  from  earlier  and 
lower  nations,  and  partly  from  barbarians  and  savages. 
In  the  public  life  of  states  this  contradiction  is  much 
more  striking  than  in  the  private  life  of  the  family  or  the 
individual.  Whereas  the  milder  teaching  of  the  Chris- 
tian religion— sympathy,  love  of  one's  fellows,  patience, 
and  devotion — has  had  a  good  influence  in  many  ways, 
there  can  be  no  question  of  this  in  the  international 
relations  of  the  nations;  here  we  find  pure  egoism. 
Every  nation  seeks  to  take  advantage  of  others  by 
cunning  or  force,  and,  wherever  possible,  to  subjugate 
them:  if  they  will  not  consent,  the  brute  force  of  war 
is  employed.  Social  misery  of  all  kinds  spreads  wider 
and  wider,  almost  in  proportion  as  civilization  develops. 
Alexander  Sutherland  is  right  when  he  characterizes 
"the  leading  nations  of  Europe  and  their  offshoots" 
(in  the  United  States)  as  lower  civilized  races.  In  some 
respects  we  are  still  barbarians. 

How  far  the  bulk  of  modern  nations  still  are  from  the 
ideal  and  the  reign  of  pure  reason  can  be  seen  by  a 
glance  at  the  social,  juridical,  and  ecclesiastical  condition 
of  "these  leading  nations  of  Europe,"  either  Teutonic 
or  Latin.  We  need  only  consider  with  an  unprejudiced 
mind  the  accounts  in  our  journals  of  parliamentary  and 
legal  proceedings,  government  measures  and  social  re- 
lations, in  order  to  realize  that  the  force  of  tradition  and 
fashion  is  immense,  and  resists  the  claims  of  reason  on 
every  side.  This  is  most  clearly  seen  externally  in  the 
power  of  fashion,  especially  as  reganls  clothing.  There 
is  a  good  ground  for  the  complaint  about  "the  tyranny 
of  fashion."  However  unpractical,  ridiculous,  ugly,  and 
costly  a  new  garment  may  be,  it  becomes  popular  if  it 
is  patronized  by  authority,  or  some  clever  manufacturer 
succeeds  in  imposing  it  by  specious  advertisements. 
We  need  only  recall  the  crinoline  of  fifty  years  ago.  the 
bustle  of  twenty  years  ago,  and   the  cxjiosure  of  the 

429 


THE    WONDERS    OF    LIFE 

breast  and  back  by  low  dresses  (with  the  object  of 
sexual  excitement)  which  was  the  fashion  of  forty  years 
ago.^  For  centuries  we  have  had  the  pernicious  fashion 
of  the  corset,  an  article  that  is  as  offensive  from  the 
aesthetic  as  from  the  hygienic  point  of  view.  Thousands 
of  women  are  sacrificed  every  year  to  this  pitiful  fashion, 
through  disease  of  the  liver  or  lungs;  nevertheless,  the 
craze  for  the  hour-glass  shape  of  the  female  form  con- 
tinues, and  the  reform  of  clothing  makes  little  headway. 
It  is  just  the  same  with  numbers  of  fashions  in  the 
home  and  in  society,  of  devices  in  commerce  and  laws 
in  the  state.  Everywhere  the  demands  of  reason  ad- 
vance little  in  their  struggle  with  the  venerable  usages 
of  tradition. 

A  false  sense  of  honor  dominates  our  social  life,  just 
as  a  false  sense  of  modesty  controls  our  clothing.  The 
true  honor  of  man  or  woman  consists  in  their  inner 
moral  dignity,  in  the  determination  to  do  only  what  they 
conceive  to  be  good  and  right,  not  in  the  outer  esteem 
of  their  fellows  or  in  the  worthless  praise  of  a  conven- 
tional society.  Unfortunately,  we  have  to  admit  that 
in  this  respect  we  are  still  largely  ruled  by  the  foolish 
views  of  a  lower  civilization,  if  not  of  crude  barbarians. 

In  many  other  features  of  our  life  besides  this  false 
modesty  and  false  honor  we  perceive  the  force  of  social 
usage.  Many  of  what  are  thought  to  be  honorable 
customs  are  relics  of  barbarism;  much  of  our  morality 
is,  in  the  light  of  pure  reason,  downright  immorality. 
As  even  the  latter  is  due  to  adaptation,  and  as  the  same 
custom  may  be  at  one  time  thought  useful  and  fitting, 
at  another  time  injurious  and  bad,  we  see  again  that  it 
is  impossible  to  restrict  the  idea  of  adaptation  to  useful 
variations.     We  may  say  the  same  of  the  changing  rules 

'  At  the  moment  I  translate  this,  telej^rams  from  Germany 
announce  that,  by  the  emperor's  orders,  a  number  of  ladies  were 
excluded  from  the  opera  for  not  observing  this  custom. — Trans. 

430 


MORA  M  T  V 

of  education,  commerce,  Ic^Mslation,  and  so  on.  The 
ideal  in  all  departments  of  life  is  pure  reason;  but  it  has 
to  struggle  long  against  the  current  prejudices  and  cus- 
toms, which  find  their  chief  support  in  the  superstitions 
of  the  Church  and  the  conservative  tendencies  of  the 
state.  In  this  state  of  Byzantine  immorality,  decorat- 
ing itself  so  often  with  the  mantle  of  piety,  practical 
materialism  flourishes,  while  monism,  or  theoretical  ma- 
terialism, is  thrust  aside. 

If  we  sum  up  all  that  monistic  science  has  taught  us 
as  to  the  origin  and  development  of  morality,  we  may 
put  it  in  the  following  series  of  propositions:  i.  By 
adaptation  to  difi"erent  conditions  of  life  the  simple  plasm 
of  the  earliest  organisms,  the  archigonous  monera,  under- 
goes certain  modifications.  2.  As  the  living  plasm  reacts 
on  these  influences,  and  the  reaction  is  often  repeated,  a 
habit  is  formed  (as  in  the  catalysis  of  certain  inorganic 
chemical  processes.  3.  This  habit  is  hereditary,  the 
repeated  impressions  being  fixed  in  the  nucleus  (or 
caryoplasm)  in  the  case  of  the  unicellulars.  4.  When 
hereditary  transmission  lasts  through  many  generations, 
and  is  strengthened  by  cumulative  adaptation,  it  be- 
comes an  instinct.  5.  Even  in  the  protist  coenobia  (the 
cell  -  communities  of  the  protophyta  and  protozoa) 
social  instincts  are  formed  by  association  of  cells.  6. 
The  antithesis  of  the  individual  and  social  instinct,  or  of 
egoism  and  altruism,  increases  in  the  animal  kingdom 
in  proportion  to  the  development  of  psychic  activity  and 
social  life.  7.  In  the  higher  social  animals  definite  cus- 
toms arise  in  this  way,  and  these  become  rights  and 
duties  when  obedience  to  them  is  demanded  by  the 
society  (herd,  flock,  people)  and  the  breach  of  them 
punished.  8.  Savage  races  at  the  lowest  stage,  without 
religion,  are  not  differently  related  to  their  customs  than 
the  higher  social  animals.  9.  The  higher  savages  de- 
velop religious  ideas,  combine  their  superstitious  prac- 

431 


THE    WONDERS    OF    LIFE 

tices  (fetichism  and  animism)  with  ethical  principles, 
and  transform  their  empirical  moral  laws  into  religious 
commands.  lo.  Among  barbaric,  and  more  particularly 
among  civilized,  races  definite  moral  laws  are  formed  by 
the  association  of  these  hereditary  religious,  moral,  and 
legal  ideas,  ii.  In  the  civilized  races  the  Church  formu- 
lates the  religious  commands,  and  jurisprudence  the 
legal  commands,  in  more  definitely  binding  forms;  the 
advancing  mind  remains,  however,  subject  in  many 
respects  to  Church  and  state.  12.  In  the  higher  civil- 
ized nations  pure  reason  gains  more  and  more  influence 
on  practical  life,  and  thrusts  back  the  authority  of  tra- 
dition ;  on  the  basis  of  biological  knowledge  a  rational  or 
monistic  ethic  is  developed. 


XIX 

DUALISM 

Dualistic  systems  of  Kant  I.  and  Kant  II. — His  antinomies — 
Cosmolotncal  flualism — The  two  worlds — The  world  of  Imdies 
and  the  world  of  spirits — Truth  and  fiction — Goethe  and 
Schiller — Realism  and  idealism — Ami- Kant — Law  of  sub- 
stance— Attributes  of  substance — Sensation  and  cnerjjy — 
Passive  and  active  energy — Trinity  of  substance:  matter 
force,  and  sensation — Constancy  f)f  sensation — Psyche  and 
physics — Reconciliation  of  principles. 

THE  history  of  j)hilosophy  shows  how  tbe  mind  of 
man  has  pressed  along  many  patbs  during  the  last 
two  thousand  years  in  ])ursuit  of  truth.  Hut,  however 
varied  are  the  systems  in  which  its  efforts  have  found 
embodiment,  we  may,  from  a  general  i)oint  of  view,  ar- 
range them  all  in  two  conflicting  series— monism,  or  the 
philosophy  of  unity;  and  dualism,  or  the  philosophy 
of  the  dualitv  of  existence.  Lucretius  and  Spinoza  are 
distinguisliod  and  typical  rcj^resentatives  of  monism: 
Plato  and  Descartes  the  great  leaders  of  dualism.  Hut 
besides  the  consistent  thinkers  of  each  school  there  are 
a  number  of  philosophers  who  vacillate  between  the  two, 
or  who  have  held  both  views  at  different  periods  of  life. 
Such  contradictions  represent  a  personal  dualism  on  the 
part  of  the  individual  thinker.  Immanuel  Kant  is  one 
of  the  most  famous  instances  of  this  class;  and  as  his 
critical  philosophy  has  had  a  profound  influence,  and  I 
was  compelled  to  contrast  my  chief  conclusions  with 
those  of  Kant,  I  must  once  more  deal  briefly  with  his 
38  43.^ 


u-- 


THE    WONDERS    OF    LIFE 

ideas.  This  is  the  more  necessary  as  one  of  the  ablest 
of  the  many  attacks  on  the  Riddle,  the  Kant  against 
Haeckel  of  Erich  Adick,  of  Kiel,  belongs  to  this  school. 

In  the  Creed  of  Pure  Reason,  which  I  published  as  an 
appendix  to  the  popular  edition  of  the  Riddle  in  1903, 
I  pointed  out,  in  view  of  this  and  similar  Kantist  criti- 
cisms, the  clear  inconsistency  of  the  great  evolutionary 
principles  of  Kant,  the  natural  philosopher,  with  the 
mystic  teaching  which  he  afterwards  made  the  founda- 
tion of  his  theory  of  knowledge,  and  that  is  still  greatly 
esteemed.  Kant  I.  explained  the  constitution  and  the 
mechanical  origin  of  the  universe  on  Newtonian  prin- 
ciples, and  declared  that  mechanicism  alone  afforded  a 
real  explanation  of  phenomena;  Kant  II.  subordinated 
the  mechanical  principle  to  the  teleological,  explaining 
everything  as  a  natural  design.  Kant  I.  convincingly 
proved  that  the  three  central  dogmas  of  metaphysics 
— God,  freedom,  and  immortality — are  inaccep table  to 
pure  reason.  Kant  II.  claimed  that  they  are  necessary 
postulates  of  practical  reason.  This  profound  opposi- 
tion of  principles  runs  through  Kant's  whole  philosophic 
work  from  beginning  to  end,  and  has  never  been  recon- 
ciled. I  had  already  shown  in  the  History  of  Creation 
that  this  inconsistency  has  a  good  deal  to  do  with  Kant's 
position  in  regard  to  evolution.  However,  this  radical 
contradiction  of  Kant's  views  has  been  recognized  by  all 
impartial  critics.  It  has  lately  been  urged  with  great 
force  by  Paul  Ree  in  his  Philosophy  (1903).  We  need 
not,  therefore,  linger  in  proving  the  fact,  but  may  go 
on  to  consider  the  causes  of  it. 

A  subtle  and  comprehensive  thinker  like  Kant  was 
naturally  perfectly  conscious  of  the  existence  of  this 
inconsistency  of  his  dualistic  principles.  He  endeavored 
to  meet  it  by  his  theory  of  antinomies,  declaring  that 
pure  reason  is  bound  to  land  in  contradictions  when  it 
attempts  to  conceive  the  whole  scheme  of  things  as  a 

434 


D  U  A  I.  1  .s  M 

connected  totality.  In  every  attempt  to  form  a  unified 
and  complete  view  of  things  we  encounter  these  un- 
solvable  antinomies,  or  mutually  contradictory  theses, 
for  both  of  which  sound  proof  is  available.  Thus,  for 
instance,  physics  and  chemistry  say  that  matter  must 
consist  of  atoms  as  its  sim])lest  particles;  but  loj^ic 
declares  that  matter  is  tli visible  in  infinitum.  On  the 
one  theory  time  and  space  are  infinite;  on  the  other 
theory,  finite.  Kant  attcmi)ted  to  reconcile  the.se  con- 
tradictions by  his  transcendental  idealism,  by  the  as- 
sumption that  objects  and  their  ccjnnection  exist  only  in 
our  imagination,  and  not  in  themselves.  In  this  way  he 
came  to  frame  the  false  theory  of  knowledge  which  is 
honored  with  the  title  of  "criticism,"  while  as  a  matter 
of  fact  it  is  only  a  new  form  of  dogmatism.  The  an- 
tinomies are  not  expla  ned  by  it,  but  thrust  aside;  nor 
was  there  more  truth  in  the  assertion  that  equal  proof 
is  available  for  theses  and  antitheses. 

The  famous  work  of  Kant's  earlier  years,  Tlic  General 
Natural  History  and  Theory  of  the  Heavens  (1755),  w:is 
purely  monistic  in  its  chief  features.  It  embodied  a  fme 
attempt  "to  explain  the  constitution  and  mechanical 
origin  of  the  universe  on  Newtonian  principles."  It  was 
mathematicallv  established  fortv  vears  afterwards  bv 
Laplace  in  his  Exposition  dn  systeme  du  monde  (1796). 
This  fearless  monistic  thinker  was  a  consistent  atheist, 
and  told  Napoleon  I.  that  there  was  no  room  for  "God" 
in  his  Mccanique  celeste  (1799).  Kant,  however,  after- 
wards found  that,  though  there  was  no  rational  evidence 
of  the  existence  of  God,  we  must  admit  it  on  moral 
grounds.  He  said  the  same  of  the  immortality  of  the 
soul  and  the  freedom  of  the  will.  He  then  constructed 
a  special  "intelligible  world"  to  receive  these  three  ob- 
jects of  faith;  he  declared  that  the  moral  sense  com- 
pelled us  to  believe  in  a  supersensual  world,  although 
pure  theoretical  reason  is  quite  unable  to  form  any  dis- 

435 


THE    WONDERS    OF    LIFE 

tinct  idea  of  it  Tlie  categorical  imperative  was  sup- 
posed to  determine  our  moral  sense  and  the  distinction 
between  good  and  evil.  In  the  further  progress  of  his 
ethical  metaphysics  Kant  expressly  urged  that  practical 
reason  should  take  precedence  of  theoretical — in  other 
words,  that  faith  is  superior  to  knowledge.  In  this  way 
he  enabled  theology  and  irrational  faith  to  find  a  place 
in  his  system  and  claim  supremacy  over  all  rational 
knowledge  of  nature. 

The  older  Greek  philosophy  had  been  purely  monistic, 
Anaximander  and  his  disciple  Anaximenes  (in  the  sixth 
century  B.C.)  conceiving  the  world  in  the  sense  of  our 
modem  hylozoism,  but  Plato  introduced  (two  hundred 
years  afterwards)  the  dualistic  view  of  things.  The  world 
of  bodies  is  real,  accessible  to  our  sensible  experience, 
changeable  and  transitory ;  opposed  to  it  is  the  world  of 
spirits,  only  to  be  reached  by  thought,  supersensual, 
ideal,  immutable,  and  eternal.  Material  things,  the 
objects  of  physics,  are  only  transient  symbols  of  the 
eternal  ideas,  which  are  the  subject  of  metaphysics. 
Man,  the  most  perfect  of  all  things,  belongs  to  both 
worlds;  his  material  frame  is  mortal,  the  prison  of  the 
immortal  and  invisible  soul.  The  eternal  ideas  are  only 
embodied  for  a  time  in  the  world  of  bodies  here  below ; 
they  dwell  eternally  in  the  world  of  spirits  beyond, 
where  the  supreme  idea  (God,  or  the  idea  of  the  good) 
controls  all  in  perfect  unity.  The  human  soul,  endowed 
with  free-will,  is  bound  to  develop  the  three  cardinal 
virtues  (wisdom,  fortitude,  and  prudence)  by  the  cultiva- 
tion of  its  three  chief  moral  faculties  (thought,  courage, 
and  zeal).  These  fundamental  principles  of  Plato's 
teaching,  s^^stematically  presented  by  his  pupil  Aristotle, 
met  with  a  very  general  acceptance,  as  they  could  easily 
be  combined  with  the  teaching  of  Christianity  which 
arose  four  hundred  years  afterwards.  The  great  majority 
of  later  philosophic  and  religious  systems  followed  the 

436 


D  U  A  L  1  S  M 

same  dualistic  paths.  Even  Kant's  metaphysics  is  only  a 
new  form  of  it;  only  its  dogmatic  character  is  hidden 
by  the  ascription  to  it  of  the  convenient  title  of  the 
"critical"  system. 

Modern  science  has  opened  out  to  us  immense  depart- 
ments of  the  real  world  that  are  accessible  to  observa- 
tion and  rational  inquiry ;  but  it  has  not  taught  us  a 
single  fact  that  ])oints  to  the  existence  of  an  immaterial 
world.  On  the  contrary,  it  has  shown  more  and  more 
clearly  that  the  supposed  world  beyond  is  a  pure  fiction, 
and  only  merits  to  be  treated  as  a  subject  for  poetry. 
Physics  and  chemistry  in  particular  have  proved  that 
all  phenomena  that  come  under  our  observation  depend 
on  physical  and  chemical  laws,  and  that  all  can  be  traced 
to  the  comprehensive  and  unified  law  of  substance.  An- 
thropogeny  has  taught  us  the  evolution  of  man  from 
animal  ancestors.  Comparative  anatomy  and  ])hysiol- 
ogy  have  shown  that  his  mind  is  a  function  of  the  brain, 
and  his  will  not  free;  and  that  his  soul,  absolutely  bound 
up  with  its  material  or^^an,  passes  away  at  death  like 
the  souls  of  other  mammals.  Finally,  modern  cos- 
mology and  cosmogony  have  found  no  trace  whatever 
of  the  existence  and  activity  of  a  personal  and  extra- 
mundane  God.  All  that  comes  within  the  range  r^f  mir 
knowledge  is  a  part  of  the  material  world. 

In  his  observations  on  the  supersensual  world  Kant 
lays  stress  on  the  fact  that  it  lies  beyond  the  range  of 
experience,  and  is  known  only  by  faith.  Conscience,  he 
thinks,  assures  us  of  its  existence,  but  does  not  give  us 
any  idea  of  its  nature;  and  so  the  three  central  mysteries 
of  metaphysics  are  mere  words  without  meaning.  Rut, 
as  nothing  can  be  done  with  mere  words,  Kant's  followers 
have  attempted  to  put  a  positive  substance  into  them. 
generally  in  relation  to  traditional  ideas  and  religious 
dogmas.  Not  only  orthodox  Kantians.  but  even  critical 
philosophers  like  Schleiden,  have  dogmatically  asserted 

437 


THE    WONDERS    OF    LIFE 

that  Kant  and  his  disciples  have  estabHshed  the  tran- 
scendental ideas  of  God,  freedom,  and  immortality,  just 
as  Kepler,  Newton,  and  Laplace  established  the  laws  of 
celestial  motion.  Schleiden  imagined  that  this  dogmatic 
affirmation  would  refute  "the  mateiialism  of  modem 
German  science."  Lange  has  shown,  on  the  contrary, 
that  such  dogmatism  is  utterly  foreign  to  the  spirit  of 
the  Critique  of  Pure  Reason,  and  that  Kant  held  the 
three  ideas  to  be  quite  incapable  of  either  positive  or 
negative  proof,  and  so  thrust  them  into  the  domain  of 
practical  philosophy.  Lange  says:  "Kant  would  not 
see,  as  Plato  would  not  see  before  him,  that  the  intelligi- 
ble world  is  a  world  of  poetry,  and  has  no  value  except 
in  this  respect."  But  if  these  ideas  are  mere  figments 
of  the  poetic  imagination,  if  we  can  form  neither  positive 
nor  negative  idea  of  them,  we  may  well  ask:  What  has 
this  imaginary  spirit-world  to  do  with  the  pursuit  of 
truth? 

As  I  have  raised  the  question  of  the  limits  of  truth 
and  fiction,  I  may  take  the  opportunity  of  pointing  out 
the  general  importance  of  this  distinction.  Undoubt- 
edly man's  knowledge  is  limited,  from  the  very  nature  of 
our  faculties  or  the  organization  of  our  bram  and  sense- 
organs.  Hence,  Kant  is  right  when  he  says  that  we 
perceive  only  the  phenomena  of  things,  and  not  their 
inner  essence,  which  he  calls  the  "  thing  in  itself."  But 
he  is  wrong  and  altogether  misleading  when  he  goes  on 
to  doubt  the  reality  of  the  external  world,  and  says  it 
exists  only  in  our  presentations — in  other  words,  that 
life  is  a  dream.  It  does  not  follow,  from  the  fact  that 
our  senses  and  phronema  can  reach  only  a  part  of  the 
properties  of  things,  that  we  call  into  question  their 
existence  in  time  and  space.  But  our  rational  craving 
for  a  knowledge  of  causes  impels  us  to  fill  up  the  gaps 
in  our  empirical  knowledge  by  our  imagination,  and 
thus  form  an  approximate  idea  of  the  whole.     This  work 

438 


DUALISM 

of  the  imagination  may  be  called  "fiction"  in  a  broad 
sense— hypotheses  when  they  are  in  science,  faith  when 
they  belong  to  religion.  However,  these  imaginative 
constructions  must  always  take  a  concrete  form.  As  a 
fact,  the  imagination  that  constructs  the  ideal  world  is 
never  content  merely  to  assume  its  existence,  but  al- 
ways proceeds  to  form  an  image  of  it.  Hut  these  fonns 
of  faith  have  no  theoretical  value  for  philosophy  if  they 
contradict  scientific  truth,  or  profess  to  be  more  than 
provisional  hypotheses ;  otherwise  they  may  be  of  prac- 
tical service,  but  are  theoretically  useless.  Hence  we 
fully  recognize  the  great  ethical  and  pedagogical  value 
of  poetry  and  myths,  but  are  by  no  means  disposed  to 
give  them  precedence  of  empirical  knowledge  in  our 
quest  of  the  truth.  I  agree  entirely  with  the  excellent 
criticism  of  Kant  which  Albert  Lange  gives  in  his  History 
of  Materialism  (vol.  ii.) ;  but  I  am  unable  to  follow  him 
when  he  transfers  his  idealism  from  practical  to  theo- 
retical questions,  and  urges  the  erroneous  theory  of 
knowledge  derived  from  it  in  opposition  to  monism  and 
realism.     It  is  true  that,  as  Lange  says: 

Kant  did  not  lack  the  sense  for  the  conception  of  this  intelligi- 
ble world  (as  an  ima.i^inative  world) ;  but  his  whi)le  education 
and  the  period  in  which  his  mental  life  developed  prevented  him 
from  indulginjT  it.  As  he  was  denied  the  Hberty  of  piN'inj,'  a 
noble  form,  free  from  all  niedian-al  distortion,  to  the  vast  slrxicturc 
of  his  ideas,  his  positive  philos(Ji)hy  was  never  fully  develoi)ed. 
His  system,  with  its  Janus  face,  stands  at  the  limit  of  two  ages. 
He  himself,  in  spite  of  all  the  defects  of  his  deductions,  is  a 
teacher  of  the  ideal.  Schiller  especially  has  grasiKvl  with  pro- 
phetic insi.i,'ht  the  very  essence  of  his  teachinj^,  and  purified  it 
of  its  scholastic  dross.  Kant  held  that  we  must  only  think, 
not  see,  the  intcllii,Mble  world;  thou;,'h  what  he  thinks  must 
have  objective  reality.  Schiller  has  rightly  brought  the  intel- 
lij^ible  world  visibly  before  us  by  treating  it  as  a  poet,  and  thus 
followin.cj  in  the  footsteps  of  Plato,  who.  in  contradiction  to  his 
own  dialectic,  reached  his  highest  thought  when  he  allowe<l  the 
supersensual  to  become  a  thing  of  sense  in  the  myth.     Schiller, 

439 


THE    WONDERS    OF    LIFE 

the  poet  of  freedom,  dared  to  carry  freedom  openly  into  the  land 
of  dreams  and  of  shadows ;  then  there  arose  under  his  hand  the 
dreams  and  shadows  of  the  ideal. 


In  view  of  the  great  influence  that  Schiller's  idealism  has 
had  in  the  spread  of  Kant's  practical  moral  philosophy, 
we  may  for  a  moment  consider  it  in  contrast  with  the 
realistic  views  of  Goethe. 

The  profound  opposition  of  the  views  of  the  two  great- 
est poets  of  the  classical  period  of  German  literature  is 
rooted  deep  in  their  natures.  This  has  been  proved  so 
often  and  so  thoroughly,  and  has  so  frequently  been 
represented  as  the  complementary  quality  of  the  two 
poets,  that  I  need  merely  recall  it  here.  As  for  Goethe, 
I  have,  in  my  General  Morphology,  shown  his  historical 
importance  in  connection  with  the  theory  of  evolution 
and  the  system  of  monism.  With  all  his  versatile  oc- 
cupations, this  great  genius  found  time  to  devote  to  the 
morphological  study  of  organisms,  and  to  establish  his 
comprehensive  biological  theories  on  this  empirical  basis. 
His  discovery  of  the  metamorphosis  of  plants  and  his 
vertebral  theory  of  the  skull  justify  us  in  classifying  him 
as  one  of  the  chief  forerunners  of  Darwin.  When  I 
dealt  v/ith  this  in  the  fourth  chapter  of  the  History  of 
Creation,  I  pointed  out  how  great  an  influence  these 
morphological  studies,  together  with  his  idea  of  evohi- 
tion,  had  on  the  realism  of  his  philosophy.  They  led 
him  direct  to  monism  and  to  an  admiration  of  Spinoza's 
monistic  pantheism,  Schiller  had  neither  great  interest 
nor  clear  insight  for  these  studies.  His  idealistic  phi- 
losophy disposed  him  rather  to  Kant's  dualistic  meta- 
physics and  to  an  acceptance  of  the  three  central  mys- 
teries—  God,  soul,  and  freedom.  Both  Schiller  and 
Goethe  had  a  thorough  knowledge  of  anthropology  and 
psychology.  But  the  anatomic  and  physiological  studies 
that  Schiller  made  as  a  military  surgeon  had  very  little 

440 


I)  U  A  L  I  S  M 

influence  on  his  transcendental  idealism,  in  which  the 
ethical-aesthetic  element  preponderated.  On  the  other 
hand,  Goethe's  empirical  realism  was  i)rofoundly  in- 
fluenced by  his  medical  studies  at  Straslmrg,  and 
especially  by  his  later  comparative  anatomical  and  bo- 
tanical investigations  at  Jena  and  Weimar. 

The  philosophic  antithesis  which  we  thus  fmd  in  the 
biological  foundations  of  the  views  of  Goethe  and  Schil- 
ler represents  to  an  extent  the  Janus  face  that  the  philo- 
sophic genius  of  the  German  people  bears  to  our  own 
day.  Goethe,  the  realist,  penetrated  deep  into  the  em- 
pirical study  of  tlie  material  world,  and  sought,  with 
Spinoza,  to  establish  the  unity  of  the  universe.  Schiller, 
the  idealist,  lives  rather  in  the  spirit-world,  and  seeks, 
with  Kant,  to  utilize  its  ethical  ideals — God,  freedom, 
and  immortality — for  the  education  of  the  human  race. 
Both  tendencies  of  thought  have  led  the  genius  of  Ger- 
many— like  the  genius  of  Greece,  two  thousand  years 
ago — to  a  great  number  of  vast  intellectual  achieve- 
ments. Goethe  wrought  the  ideal  in  his  practical  life, 
Kant  discovered  it,  Schiller  proclaimed  it  to  be  the 
fittest  aim  of  the  future. 

It  is  wrong  to  conclude  from  isolated  quotations  from 
Goethe  that  he  occasionally  betrayed  the  dualism  of 
Schiller  in  liis  opinions.  Some  of  the  remarks  in  this 
connection  that  Eckermann  has  left  us  from  his  con- 
versations with  Goethe  must  be  taken  very  carefully. 
Generally  speaking,  this  source  is  not  reliable;  many  of 
the  observations  tliat  the  mediocre  Kckermann  puts  into 
the  mouth  of  the  great  Goetlie  are  quite  inconsistent 
with  his  character,  and  are  more  or  less  ])erverted. 
Hence,  when  ^ecent  high-jilaced  orators  declare  at  Ber- 
lin that  Goethe  saved  the  high  ideals  of  God,  freedom, 
and  immortality,  like  Schiller,  and  thus  borrow  a  certain 
support  for  their  Christian  belief,  they  only  show  how 
little  they  have  grasped  the  profound  antithesis  of  the 

441 


THE    WONDERS    OF    LIFE 

views  of  the  two  poets.  Goethe  notoriously  described 
himself  as  a  "renegade  non-Christian."  The  creed  of 
the  "great  heathen"  Goethe,  as  we  find  it  in  Faust  and 
Prometheus  and  God  and  the  World,  and  a  hundred  other 
magnificent  poems,  is  pure  monism,  of  the  pantheistic 
character  which  we  take  to  be  alone  correct — hylozoism ; 
he  is  equally  far  from  the  one  -  sided  materialism  of 
Holbach  or  Carl  Vogt  and  the  extreme  dynamism  of 
Leibnitz  and  Ostwald.  Schiller  by  no  means  shared 
this  realistic  view  of  things;  his  idealistic  sense  fled  be- 
yond nature  into  the  spirit  world.  However,  our  theo- 
retic hylozoism  does  not  exclude  practical  idealism,  as 
Goethe's  whole  life  showed.  On  the  other  hand,  princes 
and  priests  often  let  us  see  how  easily  theoretical  ideal- 
ism goes  with  practical  materialism,  or  hedonism. 

In  the  month  of  February,  1904,  the  centenary  of 
the  death  of  Kant  was  celebrated  throughout  the  world 
of  culture.  In  numbers  of  academic  speeches  and  writ- 
ings he  was  greeted  as  the  greatest  thinker  of  Germany. 
He  died  on  the  same  date  (February  12th)  on  which  Dar- 
win was  born  five  years  later.  It  is  unquestionable 
that  Kant  has  had  an  immense  influence  on  the  whole 
development  of  German  philosophy.  But  while  recog- 
nizing his  extraordinary  genius,  we  must  not  be  blind  to 
the  glaring  contradictions  and  defects  of  his  dualist 
system.  From  the  monistic  point  of  view,  we  can  only 
regard  his  profound  influence  during  the  whole  of  the 
nineteenth  century  as  mischievous.  Most  certainly  he 
had  a  quite  exceptional  talent  for  philosophic  specula- 
tion and  penetrating  thought,  and  he  added  to  his  great 
mental  qualities  a  blameless  character  and  an  undeni- 
able sense  of  truth  in  life  (though  not  in  thought).  It 
was  a  serious  misfortune  for  Kant  and  for  the  philo- 
sophic school  he  led  that  his  education  prevented  him 
from  acquiring  a  thorough  knowledge  and  correct  con- 
ception  of   the   real  world.     Shut  up   throughout  life 

442 


1)U  ALI  SM 

within  the  narrow  bounds  of  his  native  town.  K^nigs- 
berg,  he  never  travelled  beyond  the  frontier  of  Prussia, 
and  so  did  not  obtain  that  knowledge  of  the  world  that 
comes  of  travelling.  In  the  study  of  nature  he  con- 
fined himself  to  the  physics  of  the  inorganic  world,  in 
the  study  of  man  to  the  immortal  soul.  At  the  close  of 
his  university  studies  Kant  had  to  earn  his  living  as  a 
house-teacher  for  nine  vears  (from  twentv-two  to  thirtv- 
one),  just  at  the  most  important  period  of  his  life,  in 
which  the  independent  development  of  the  personal  and 
scientific  character  is  decided  when  the  academic  studies 
are  over. 

In  such  adverse  circumstances  of  mental  adaptation 
a  deep  mystic  trait,  which  had  been  inherited  from 
pious  parents  and  confimied  by  the  strictly  religious 
training  of  his  early  years,  was  fixed  in  Kant's  character. 
Hence  it  was  that  faith  in  the  three  central  mysteries 
came  upon  him  more  and  more  in  later  years:  he  gave 
them  precedence  over  all  the  attainments  of  theoretical 
reason,  while  granting  that  we  can  form  neither  a  nega- 
tive nor  positive  idea  of  them.  Hut  how  can  the  belief 
in  God,  freedom,  and  immortality  determine  one's  whole 
view  of  life  as  a  postulate  of  practical  reason  if  we  can- 
not form  any  definite  idea  of  them  ? 

Every  philosophy  that  deserves  the  name  must  have 
clear  ideas  as  the  bases  of  its  thought-structure;  it  must 
have  definite  views  in  connection  with  its  fundamental 
conceptions.  Hence  most  of  Kant's  followers  have  not 
been  content  to  follow  his  direction  merely  to  Miei'c  in 
the  three  central  mysteries;  they  have  sought  to  as- 
sociate definite  mental  pictures  with  the  empty  concepts 
of  God,  freedom,  and  immortality.  In  this  they  have 
drawn  upon  the  religious  imagination,  and  have  pa.«yM?d 
from  the  real  knowledge  of  nature  into  the  transcenden- 
tal realm  of  poetry.  Monism,  based  on  this  real  knowl- 
edge of  nature,  has  to  keej)  clear  of  such  dualism. 

443 


THE    WONDERS    OF    LIFE 

The  extraordinary  glorification  of  Kant  that  took 
place  on  the  occasion  of  his  centenary  must  have  seem- 
ed strange  to  many  scientists  who  recognize  in  his  ideal- 
ism one  of  the  greatest  hinderances  to  the  spread  of  the 
modern  monistic  philosophy  of  nature.  But  it  is  not 
difficult  to  explain  this.  We  must  remember,  in  the 
first  place,  the  contradictory  views  that  are  embodied 
in  Kant's  system ;  every  one  could  find  in  Kant's  works 
something  to  correspond  to  his  own  convictions — the 
monistic  physicist  could  read  of  the  mechanical  sway  of 
natural  law  throughout  the  whole  knowable  world,  and 
the  dualistic  metaphysician  of  the  free  play  of  the  divine 
aim  in  the  spiritual  world.  The  physician  and  physi- 
ologist would  note  with  satisfaction  that  in  his  criticism 
of  pure  reason  Kant  had  been  unable  to  find  any  evi- 
dence for  the  existence  of  God,  the  immortality  of  the 
soul,  or  the  freedom  of  the  will.  The  jurist  and  theo- 
logian would  find  with  equal  gratification  that  in  the 
practical  reason  Kant  claims  these  three  central  dogmas 
as  necessary  postulates.  I  have  shown  to  some  extent, 
in  the  sixth  chapter  of  the  Riddle,  how  these  irreconcil- 
able contradictions  in  Kant's  system  are  due  to  a  psy- 
chological metamorphosis. 

It  is  just  these  very  contradictions,  which  run  through 
Kant's  philosophy  from  beginning  to  end,  that  maintain 
its  popularity.  Educated  people  v/ho  desire  to  form  a 
view  of  life  rarely  read  Kant's  difficult  (and  often  ob- 
scure) works  in  the  original,  but  are  content  to  learn 
from  extracts,  or  from  a  history  of  philosophy,  that  the 
Konigsberg  thinker  succeeded  in  squaring  the  circle,  or 
in  reconciling  natural  science  with  the  three  central 
dogmas  of  metaphysics.  The  "higher  powers,"  who 
are  particularly  concerned  to  save  the  latter,  favor  the 
teaching  of  Kant's  dogmas,  because  it  closes  the  way  to 
real  explanation  and  prevents  independent  thinking. 
This  is  especially  true  of  the  ministers   of  public  in- 

444 


DUALISM 

struction  in  the  two  chief  German  states — Prussia  and 
Bavaria.  In  their  open  attempt  to  subordinate  the 
school  to  the  Church,  they  desire,  above  all,  the  primacy 
of  practical  reason — that  is  to  say,  the  subjection  of 
pure  reason  to  faith  and  revelation.  In  German  uni- 
versities to-day  belief  in  Kant  is  a  sort  of  ticket  of  ad- 
mission to  the  study  of  philosophy.  The  reader  who 
would  realize  the  pernicious  effect  of  this  official  faith 
in  Kant  on  the  advance  of  scientific  knowledge  will  do 
well  to  read  the  able  criticism  in  the  brilliant  posthu- 
mous work  of  Paul  Rce. 

In  the  face  of  the  dualism  which  still  prevails  in  the 
academic  teaching  of  philosophy  (especially  in  Germany) 
we  must  base  our  monistic  system  on  the  universality  of 
the  law  of  substance.  This  harmoniously  combines  the 
laws  of  the  conservation  of  matter  and  of  energy.  As  I 
have  fully  explained  my  own  conception  of  this  law  in 
the  twelfth  chapter  of  the  Riddle,  I  will  only  say  here 
that  its  validity  is  quite  independent  of  any  particular 
theory  of  the  relations  of  matter  and  force.'  The 
materialism  of  Holbach  and  Biichner  lays  a  one-sided 
stress  on  the  importance  of  matter:  the  dynamism  of 
Leibnitz  and  Ostv/ald  on  that  of  force.  If  we  avoid  these 
extremes,  and  conceive  matter  and  force  as  inseparable 
attributes  of  substance,  we  have  pure  monism,  as  we  find 
it  in  the  systems  of  Spinoza  and  Goethe.  We  might 
then  substitute  for  the  word  "substance,"  as  Hermann 
Croll  does,  the  temi  "force-matter."  The  further  ques- 
tion as  to  the  correctness  of  any  particular  physical  con- 
ception of  matter  is  quite  independent  of  this. 

'  The  English  reader  will  find  in  this  a  reply  to  the  fooh'sh  notion 
which  has  been  circulated  that  the  recent  discovery  of  radio- 
action  and  the  compcfsition  of  the  atom  from  electrons  has  af- 
fected llacckcrs  position.  His  monism  is  completely  indiffer- 
ent to  chani^es  in  the  physicist  conception  fif  the  nature  of  mat- 
ter.— Trans. 

445 


THE    WONDERS    OF    LIFE 

The  two  knowable  attributes  or  inalienable  properties 
of  substance,  without  which  it  is  unthinkable,  were  de- 
scribed by  Spinoza  as  extension  and  thought;  we  speak 
of  them  as  matter  and  force.  The  "extended"  (or 
space-occupying)  is  matter;  and  in  Spinoza  "thought" 
does  not  mean  a  particular  function  of  the  human  brain, 
but  energy  in  the  broadest  sense.  While  hylozoistic 
monism  conceives  the  human  soul  in  this  sense  as  a 
special  form  of  energy,  the  current  dualism  or  vitalism 
affirms,  on  the  authority  of  Kant,  that  psychic  and 
physical  forces  are  essentially  different;  that  the  former 
belong  to  the  immaterial  and  the  latter  to  the  material 
world.  The  theory  of  psycho-physical  parallelism,  as 
developed  especially  by  Wundt  (1892),  gives  a  very 
sharp  and  definite  expression  to  this  dualism;  it  says 
that  "physical  processes  correspond  to  every  psychic 
phenomenon,  but  the  two  are  completely  indepen- 
dent of  each  other  and  have  no  natural  causal  connec- 
tion." 

This  wide-spread  dualism  finds  its  chief  support  in  the 
difficulty  of  directly  connecting  the  processes  of  sensa- 
tion with  those  of  movement ;  and  so  the  one  is  regarded 
as  a  psychic  and  the  other  ac  a  physical  form  of  energy. 
The  conversion  of  the  outer  stimulus  (waves  of  light, 
sound,  etc.)  into  an  inner  sensation  (sight  or  hearing)  is 
regarded  by  monistic  physiology  as  a  conversion  of 
force,  a  transformation  of  photic  or  acoustic  energy 
into  specific  nerve-energy.  The  important  theory  of 
the  specific  energy  of  the  sensory  nerves,  as  formulated 
by  Johannes  Miiller,  forms  a  bridge  between  the  two 
worlds.  But  the  idea  which  these  sensations  evoke, 
the  central  process  in  the  thought-organ  or  phronema 
that  brings  the  impressions  into  consciousness,  is  gen- 
erally regarded  as  an  incomprehensible  mystery.  How- 
ever, I  have  endeavored  to  prove,  in  the  tenth  chapter 
of  the  Riddle,  that  consciousness  itself  is  only  a  special 

446 


D  U  A  L  I  S  M 

form  of  nervous  energy,  and  Ostwald  has  lately  devel- 
oped the  theory  in  his  Natural  Philosophy. 

The  processes  of  movement  v/hich  we  observe  in  every 
change  of  one  form  of  energy  into  another,  or  every 
passage  of  potential  into  actual  energy,  are  subordinate 
to  the  general  laws  of  mechanics.  The  dualist  meta- 
physic  has  rightly  said  that  the  mechanical  philosophy 
does  not  discover  the  inner  causes  of  these  movements. 
It  would  seek  these  in  psychic  forces.  On  our  monistic 
principles  they  are  not  immaterial  forces,  but  based  on 
the  general  sensation  of  substance,  which  wc  call  psy- 
choma,  and  add  to  energy  and  matter  as  a  third  attri- 
bute of  substance. 

The  difficulty  of  combining  our  monism  with  Spinoza's 
doctrine  of  substance  is  met  by  detaching  the  idea  of 
energy  from  sensation  and  restricting  it  to  mechanics,  so 
as  to  make  movement  a  third  fundamental  property  of 
substance  with  matter  (the  "extended")  and  sensation 
(the  "thinking").  We  may  also  divide  energy  into 
active  (r=will  in  the  sense  of  Schopenhauer)  and  i)as- 
sive  (=  sensation  in  the  broadest  sense).  As  a  matter 
of  fact,  the  energy  to  which  modern  encrgism  would  re- 
duce all  phenomena  has  not  an  independent  place  in 
Spinoza's  system  besides  sensation ;  the  attribute  of 
thought  (the  psyche,  soul,  force)  comprises  the  two.  I 
am  convinced  that  sensation  is,  like  movement,  found  in 
all  matter,  and  this  trinity  of  substance  i)rovidcs  the 
safest  basis  for  modern  monism.  I  may  formulate  it  in 
three  propositions:  (i)  No  matter  without  force  and 
without  sensation.  (2)  No  force  without  matter  and 
without  sensation.  (3)  No  sensation  without  matter 
and  without  force.  These  three  fundamental  attributes 
are  found  inseparably  united  throughout  the  whole 
universe,  in  every  atom  and  every  molecule.  In  view 
of  the  great  importance  of  this  view  for  our  hylonistic 
system  of  monism,  it  may  be  well  to  consider  each  of 

447 


THE    WONDERS    OF    LIFE 

these  three  attributes  in   connection  with  the  law  of 
substance. 

A.  Matter. — As  extended  substance,  matter  occupies 
infinite  space,  and  each  individual  body  forms  a  part  of 
the  universe  as  real  substance.  The  law  of  the  conserva- 
tion of  matter  teaches  us  that  the  sum  of  matter  is 
eternal  and  unchangeable.  This  applies  equally  to  the 
various  kinds  of  matter  which  we  call  the  chemical 
elements,  or  ponderable  matter,  and  to  the  ether  that 
fills  the  spaces  between  the  atoms  and  molecules,  or 
imponderable  matter.  The  mischievous  depreciation  of 
matter  (and  the  consequent  disdain  of  materialism) 
and  its  antithesis  to  "spirit"  is  partly  due  to  the  use 
of  such  phrases  as  "raw"  and  "dead"  matter,  and 
partly  to  the  deep-rooted  mysticism  we  have  inher- 
ited from  barbaric  ancestors,  and  find  it  hard  to  shake 
off. 

B.  Energy. — All  parts  of  the  substance  that  fills  in- 
finite space  are  in  constant  and  eternal  motion.  Every 
chemical  process  and  every  physical  phenomenon  is 
accompanied  by  a  change  in  the  position  of  the  particles 
v>rhich  compose  the  matter.  The  law  of  the  conserva- 
tion of  energy  teaches  us  that  the  sum  of  force  or  energy 
that  is  ever  at  work  in  the  universe  is  unchangeable.  In 
the  formation  or  decomposition  of  a  chemical  compound 
the  particles  of  matter  move  about,  and  so  in  every 
mechanical,  thermic,  electric,  and  other  process.  The 
changes  that  take  place  depend  on  a  constant  change  of 
force,  both  in  organic  and  inorganic  bodies;  one  form  of 
force  is  converted  into  another  without  a  particle  of  the 
whole  being  lost.  This  law  of  the  conservation  of  force 
has  lately  been  called,  as  a  rule,  the  conservation  of 
energy  (or  the  principle  of  energy)  since  the  ideas  of 
force  and  energy  have  been  more  clearly  distinguished 
in  physics ;  energy  is  now  usually  defined  as  the  product 
of  force  and  direction.     It  must  be  noted,  however,  that 

448 


DUALISM 

the  word  "energy"  (as  an  equivalent  to  "work"  in  the 
physical  sense)  is  still  used  in  many  different  senses,  as 
is  also  the  word  "  force."  Others  define  energy  as  "  work 
or  all  that  comes  of  work  and  may  be  converted  into 
work."  One  particular  school  of  voluntarism  (Wundt) 
reduces  the  motive-force  of  energy  to  will.  Crusius  said 
in  1744:  "Will  is  the  dominating  force  in  the  world." 
And  Schopenhauer  defines  the  world  (or  substance)  as 
"will  and  presentation." 

C.  Sens.\tion. — In  describing  sensation  (in  the  broad- 
est sense)  as  a  third  attribute  of  substance,  and  sepa- 
rating "sensitive  substance"  from  energy  as  "moving 
substance,"  I  rely  on  the  observations  I  made  in  the  thir- 
teenth chapter  of  the  Riddle  on  sensation  in  the  organic 
and  inorganic  world.  I  cannot  imagine  the  simplest 
chemical  and  physical  process  without  attributing  the 
movements  of  the  material  particles  to  unconscious  sen- 
sation. In  this  sense  the  chemist  speaks  every  day  of 
a  sensitive  reaction,  and  the  photographer  of  a  sensitive 
plate.  The  idea  of  chemical  affinity  consists  in  the  fact 
that  the  various  chemical  elements  perceive  the  quali- 
tative differences  in  otlier  elements,  experience  "pleas- 
ure" or  "revulsion"  at  contact  with  them,  and  execute 
their  specific  movements  on  this  ground.  The  sensitive- 
ness of  the  plasm  to  all  kinds  of  stimuli,  which  is  called 
"soul"  in  the  higher  animals,  is  only  a  suj^erior  degree 
of  the  general  irritability  of  substance.  Empedocles 
and  the  panpsychists  spoke  in  the  same  sense  of  sensa- 
tion and  effort  in  all  things.  As  Nageli  said:  "If  the 
molecules  possess  something  that  is  related,  however 
distantly,  to  sensation,  it  must  be  comfortable  to  be  able 
to  follow  their  attractions  and  repulsions;  uncomfortable 
when  they  are  forced  to  do  otherwise.  Thus  we  get  a 
common  spiritual  bond  in  all  material  phenomena.  The 
mind  of  man  is  only  the  highest  development  of  the 
spiritual  processes  that  animate  the  whole  of  nature." 
29  449 


THE    WONDERS    OF    LIFE 

These  views  of  the  distinguished  botanist  fully  agree 
with  my  monistic  principles. 

When  sensation  in  the  widest  sense  (as  psychoma)  is 
joined  to  matter  and  energy  as  a  third  attribute  of  sub- 
stance, we  must  extend  the  universal  law  of  the  per- 
manence of  substance  to  all  three  aspects  of  it.     From 
this  we  conclude  that  the  quantity  of  sensation  in  the 
entire  universe  is  also  eternal  and  unchangeable,  and 
that  every  change  of  sensation  means  only  the  conver- 
sion of  one  form  of  psychoma  into  other  forms.     If  we 
start  from  our  own  immediate  sensations  and  thoughts, 
and  look  out  on  the  whole  mental  life  of  humanity,  we 
see  through  all  its  continuous  development  the  constancy 
of  the  psychoma,  which  has  its  roots  in  the  sensations  of 
each  individual.     This  highest  achievement  of  the  work 
of  the  plasm  in  the  human  brain  was,  however,  first 
developed  in  the  sensations  of  the  lower  animals,  and 
these  are  in  turn  connected  by  a  long  series  of  evolu- 
tionary stages  with  the  simpler  forms  of  sensation  that 
we  find  in  the  inorganic  elements,  and  that  reveal  them- 
selves  in   chemical    affinity.     Albrecht   Rau   expressly 
says  in  his  excellent  Sensation  and  Thought  (1896)  that 
"perception  or  sensation  is  a  universal  process  in  nature. 
This   involves,   moreover,    the   possibility   of   reducing 
thought    itself    to    this    universal    process."     Recently 
Ernst  Mach  has  said,  in  his  Analysts  of  Sensation  and 
the  Relation  of  the  Physical  to  the  Psychical,  that  "sensa- 
tions are  the  common  elements  of  all  possible  physical 
and  psychic  occurrences,  and  consist  simply  in  the  dif- 
ferent mode  of  the  combination  of  the  elements  and 
their  dependence  on  each  other."     It  is  true  that  Mach, 
in  his  one-sided  emphasis  of  the  subjective  element  of 
sensation,  goes  on  to  form  a  similar  psychomonism  to 
that  of  Verworn,  Avenarius,  and  other  recent  dynamists; 
but  the  fundamental  character  of  his  system  is  purely 
monistic,  like  the  energism  of  Ostwald. 

450 


DUALISM 

In  thus  uniting  sensation  with  force  and  matter  as  an 
attribute  of  substance,  we  form  a  monistic  trinity,  and 
are  in  a  position  to  do  away  with  the  antitheses  that  are 
rigidly  maintained  by  duahsts  between  the  psychic  and 
the  physical,  or  the  material  and  the  immaterial  world. 
Of  the  three  great  monistic  systems  materialism  lays 
too  narrow  a  stress  on  the  attribute  of  matter,  and 
would  trace  all  the  phenomena  of  the  universe  to  the 
mechanics  of  the  atoms  or  to  the  movements  of  their 
ultimate  particles.  Spiritualism,  with  equal  narrow- 
ness, builds  on  the  attribute  of  energy ;  it  would  either 
explain  all  phenomena  by  motor  forces  or  forms  of 
energy  (energism),  or  reduce  them  to  psychic  functions, 
to  sensation  or  psychic  action  (panpsychism).  Our 
system  of  hylonism  (or  hylozoism)  avoids  the  faults  of 
both  extremes,  and  affirms  the  identity  of  the  psyche 
and  the  physis  in  the  sense  of  Spinoza  and  Goethe.  It 
meets  the  difficulties  of  the  older  theory  of  identity  by 
dividing  the  attribute  of  thought  (or  energy)  into  two 
co-ordinate  attributes,  sensation  (psychoma)  and  move- 
ment (mechanics). 


XX 

MONISM 

Defence  of  monism — Pure  and  applied  science  (theoretic  and 
practical  reason)  —  Pure  (theoretical)  sciences  :  physics, 
chemistry,  mathematics,  astronomy,  geology;  biology, 
anthropology,  psychology,  philology,  history — Applied 
(practical)  sciences:  medicine,  psychiatry,  hygiene,  tech- 
nology, pedagogics,  ethics,  sociology,  politics,  jurispru- 
dence, theology — Antinomy  of  the  sciences — Rational  and 
dogmatic  disciplines — Correlation  of  the  sciences — Faculties 
— Reform  of  education  —  The  ideal  world  —  Harmony  of 
monism. 

NOW  that  we  have  reached  the  end  of  our  long  jour- 
ney, we  may  take  a  general  survey  of  the  path  we 
have  pursued,  and  say  how  far  we  owe  our  progress  to 
the  monistic  philosophy.  In  doing  so,  we  shall  at  once 
justify  our  own  point  of  view  and  indicate  the  relation 
of  biology  to  the  other  sciences.  I  feel  the  more  bound 
to  do  this  as  the  present  volume  is  not  only  a  necessary 
supplement  to  the  Riddle,  but  at  the  same  time  my  last 
philosophic  work.  At  the  end  of  my  seventieth  year  I 
would  supply  some  of  the  defects  of  the  Riddle,  answer 
some  of  the  most  stringent  criticisms  directed  against 
it,  and  as  far  as  possible  complete  the  philosophy  of  life 
at  which  I  worked  for  half  a  century. 

In  inviting  my  readers  to  accompany  me  once  more 
through  the  broad  domain  of  the  monistic  philosophy  I 
must,  as  their  modest  guide,  show  scientific  justification 
at  the  narrow  entrance — produce,  so  to  say,  the  ticket 
of  admission  to  this  investigation.    The  academic  philos- 

452 


MONISM 

ophy  which  vStill  controls  the  German  universities 
watches  every  door  with  jealous  eyes,  and  has  an  es- 
pecial concern  to  keep  out  modern  biology.  OOicial 
German  philosophy  is  still  for  the  most  part  taken  up 
with  a  mediaeval  metaphysic  and  the  dualism  of  Kant, 
the  openly  dogmatic  character  of  which  it  greets  as 
"criticism."  In  the  course  of  the  forty  years  during 
which  I  have  taught  as  ordinary  professor  of  zoology  at 
Jena  I  have  had  occasion  to  assist  at  several  hundred 
examinations  of  doctors,  teachers,  etc.,  in  which  dis- 
tinguished representatives  of  philosophy  were  examiners. 
I  saw  that  nearly  always  the  chief  stress  was  laid  on  a 
kind  of  conceptual  gymnastics  and  self-observation, 
and  on  the  correct  knowledge  of  the  innumerable  errors 
which  the  (mainly  dualistic)  leaders  of  ancient  and 
modern  philosophy  have  left  us  in  their  vast  literature. 
The  central  feature  of  the  whole  scheme  is  Kant's  theory 
of  knowledge,  the  defects  and  one-sidedness  of  which  I 
have  treated  in  the  first  and  nineteenth  chapters.  In 
psychology  a  most  extensive  knowledge  of  psychic  pow- 
ers on  the  basis  of  the  introspective  method  is  demanded  ; 
the  physiological  analysis  of  the  "soul"  and  the  ana- 
tomic study  of  the  phronema  are  carefully  avoided,  as 
are  also  the  comparative  and  genetic  study  of  the  mind. 
Many  of  our  metaphysicians  go  even  farther  and  regard 
philosophy  as  a  separate  science — a  sublime  "mental 
science,"  quite  independent  of  the  common  empirical 
sciences.  One  is  tempted  to  quote  the  saying  of  Schop- 
enhauer: "It  is  a  sure  sign  of  a  philosopher  that  he  is 
not  a  professor  of  philosophy."  In  my  opinion,  every 
educated  and  thoughtful  man  who  strives  to  form  a 
definite  view  of  life  is  a  philosopher.  As  queen  of  the 
sciences,  philosoy)hy  has  the  great  task  of  combiiiing 
the  general  results  of  the  other  sciences,  and  of  bringing 
their  ravs  of  light  to  a  focus  as  in  a  concave  mirror. 
The  various  tendencies  of  thought  that  arise  in  such  num- 

45.^ 


THE    WONDERS    OF    LIFE 

bers  have  all  a  right  to  scientific  respect  and  discussion, 
the  monistic  minority  no  less  than  the  dualistic  major- 
ity. We  have  to  inquire,  then,  how  far  monism  has 
succeeded  in  gaining  firm  foothold  in  the  various  fields 
of  science,  and  we  may  begin  with  a  distinction  between 
pure  (theoretical)  and  applied  (practical)  science. 

Pure  philosophy  aims  at  a  knowledge  of  the  truth  by 
means  of  pure  reason,  as  I  explained  in  the  first  chapter. 
However,  this  theoretical  philosophy  finds  itself  in  most 
of  the  sciences  in  direct  and  frequently  important  rela- 
tions to  practical  life,  and  so  in  the  form  of  applied  philos- 
ophy becomes  a  weighty  factor  in  civilization.  In  this 
the  real  claims  of  practical  life  are  often  in  contradiction 
to  the  ideal  tenets  of  the  scientifically  grounded  theory. 
In  such  cases,  in  my  opinion,  the  pure  pursuit  of  the 
truth  must  take  precedence  of  applied  philosophy.  I 
thus  dissent  entirely  from  the  view  of  Kant,  who  ex- 
pressly gives  precedence  to  practical  reason,  and  sub- 
ordinates theoretical  reason  to  it.  Kant's  error  was 
fated  to  have  a  terrible  influence,  because  the  dominant 
authorities  in  Church  and  state  eagerly  embraced  it 
to  insure  everywhere  the  supremacy  of  the  dogmas  of 
practical  reason  over  the  attainments  of  pure  critical 
reason. 

From  the  point  of  view  of  natural  monism  we  may 
take  physics  in  the  wider  sense  as  the  fundamental 
science.  The  term  physis  (the  Greek  equivalent  of  the 
Latin  "nature"),  in  its  original  meaning,  comprises  the 
whole  knowable  world — Kant's  mundus  sensihilis.  His 
supersensual  or  "intelligible"  world  is,  on  his  own 
definition,  the  object  of  faith,  not  knowledge.  It  is  very 
remarkable  to  find  a  thinker  like  Kant  contradicting 
himself  already  in  his  fundamental  distinction  of  the 
two  worlds.  How  can  the  supersensual  world,  with  its 
three  central  mysteries  (God,  freedom,  and  immortal- 
ity), be  described  as  intelligible  (i.e.,  knowable)  when 

454 


M  O  N  I  S  M 

it  is  proved  by  pure  reason  that  the  human  mind  is  in- 
capable of  knowing  it,  or  of  forming  any  positive  or 
negative  idea  of  it?  Lucus  a  non  hicendo !  We  may, 
therefore,  leave  this  supernatural  metaphysical  world  to 
faith  and  fiction,  and  confine  our  studies  to  the  real 
physical  world,  nature.  The  idea  of  physics  as  a  com- 
prehensive natural  philosophy,  as  it  was  conceived  in 
classic  Greece,  has  been  more  and  more  restricted  in 
the  course  of  time.  To-day  it  is  generally  taken  to 
mean  the  science  of  the  ])henomena  of  inorganic  nature, 
their  empirical  determination  by  observation  and  ex- 
periment (experimental  physics),  and  their  reduction  to 
fixed  natural  laws  and  mathematical  formulae  (theo- 
retical or  mathematical  physics).  Of  late  a  distinction 
has  been  drawn  between  the  physics  of  mass  and  the 
physics  of  ether;  the  one  deals  with  mechanics,  the 
movement  and  equilibrium  of  ponderable  matter,  of 
solid,  fluid,  and  gaseous  bodies  (statics  and  dynamics, 
gravitation,  acoustics,  meteorology);  the  other  is  oc- 
cupied with  the  phenomena  of  ether  (or  imponderable 
matter)  and  its  relations  to  mass  (electricity,  galvanism, 
magnetism,  optics,  and  calorics).  In  all  these  branches 
of  inorganic  physics  the  monistic  view  is  now  generally 
received,  and  all  attempt  at  dualistic  explanation  aban- 
doned. 

The  vast  department  of  chemistry,  which  has  now 
become  so  important  both  for  theoretical  and  practical 
purposes,  is  really  only  a  part  of  physics.  But  while 
modern  physics  restricts  itself  to  the  study  of  inorganic 
forms  of  energy  and  their  conversions,  chemistry,  as  the 
science  of  matter,  takes  up  the  study  of  the  qualitative 
differences  between  the  various  kinds  of  ponderable 
matter.  It  divides  ponderable  bodies  into  some  severity- 
eight  elements,  the  relations  of  which  to  each  other  have 
been  determined  in  the  periodic  system  of  the  elements, 
and  their  probable  common  origin  from  some  primitive 

455 


THE    WONDERS    OF    LIFE 

matter  (prothyl)  been  shown.  The  constant  features  of 
chemical  combinations  which  have  been  estabUshed  by 
the  analysis  and  synthesis  of  the  elements,  and  especial- 
ly the  law  of  simple  and  multiple  proportions  discovered 
in  1808,  led  to  the  empirical  determination  of  the  atomic 
weight  of  the  elements  and  to  the  chemical  theory  of  the 
atom.  The  acceptance  of  these  atoms  (as  space-filUng 
separate  particles  of  matter — however  we  may  regard 
them  in  other  respects)  is  an  indispensable  hypothesis  in 
chemistry,  like  the  hypothesis  of  the  molecule  in  physics. 
Modern  dynamism  (or  energism)  is  wrong  when  it  thinks 
it  can  dispense  with  these  hypotheses  and  replace  the 
atoms  by  the  notion  of  immaterial  non  -  spatial  points 
of  force.  However,  in  both  the  dynamic  and  the  mate- 
rial school,  monism  is  retained  in  every  department  of 
chemistry. 

Modern  science  considers  the  ultimate  aim  of  all  re- 
search to  be  the  exact  determination  of  phenomena  in 
measure  and  number,  or  the  reduction  of  all  general 
knowledge  to  mathematically  formulated  laws.  As  the 
great  Laplace  established  his  system  mathematically,  it 
has  lately  been  claimed  that  a  comprehensive  (ideal) 
Laplace-mind  could  embrace  the  whole  past,  present, 
and  future  of  the  universe  in  a  single  gigantic  mathe- 
matical formula.  Kant  has  expressed  this  exaggerated 
estimate  of  mathematics  in  the  phrase:  "Every  science 
is  only  true  science  in  proportion  as  it  is  amenable  to 
mathematical  treatment";  and  to  this  he  has  added  the 
second  error  that  the  mathematical  axioms  (being  neces- 
sary and  universal  truths)  belong  to  the  a  priori  con- 
stitution of  the  mind,  and  are  independent  of  experience 
(a  posteriori).  However,  John  Stuart  Mill  and  others 
have  shown  that  the  fundamental  ideas  of  mathematics 
are  acquired  originally,  like  those  of  any  other  science, 
by  abstraction  from  experience;  and  the  modern  phy- 
logeny  of  the  mind  has  confirmed  this  empirical  view. 

456 


M  O  X  I  S  M 

We  must  remember,  moreover,  that  matheinatics  deals 
only  with  quantitative  relations  in  time  and  space,  and 
not  with  the  qualitative  features  of  bodies.  In  fact, 
Kant  himself  showed  that  mathematics  only  answers 
for  the  absolute  formal  correctness  of  conclusions  it  draws 
from  given  premises,  and  has  no  influence  on  the  ]jrem- 
ises  themselves.  Hence,  when  we  examine  the  ab- 
stract thinking-power  of  the  phronema  in  its  mathe- 
matical operations  physiologically  and  phylogenetically, 
we  find  that  even  this  "exact  fundamental  science"  is 
only  accessible  to  pure  monism  and  excludes  ail  dual- 
ism. The  great  regard  which  mathematics  enjoys  as  an 
exact  science  in  all  branches  of  knowledge  is  chiefly  due 
to  its  formal  accuracy,  and  to  the  possibility  of  express- 
ing infallibly  spatial  and  time  quantities  in  numVjer  and 
mass. 

Astronomy  is  one  of  the  older  sciences  that  took 
definite  shape  thousands  of  years  ago,  and  received  a 
solid  mathematical  foundation.  Observations  of  the 
movements  of  the  planets  and  eclipses  of  the  sun  were 
conducted  by  the  Chinese,  Chaldeans,  and  Egyptians 
several  thousand  years  before  Christ.  Christ  himself  had 
no  more  suspicion  of  these  great  cosmological  discoveries 
than  of  the  systems  which  the  Greek  natural  philosophers 
had  built  u])  three  hundred  to  six  hundred  years  before 
his  birth.  After  Copernicus  had  destroyed  the  geocentric 
system  in  1543,  and  Newton  had  ])rovided  a  mathe- 
matical basis  for  the  new  heliocentric  system  by  his 
theory  of  gravitation  in  1686,  cosmogony  was  -finnly 
established  in  a  monistic  sense  by  the  General  Natural 
History  of  tJie  Heavens  of  Kant,  and  the  M^^caniquc 
Celeste  of  Laplace.  Since  that  time  there  has  been  no 
question  of  the  conscious  action  of  a  Creator  in  any 
part  of  astronomy.  Astrophysics  has  enlarged  our 
knowledge  of  the  ])hysical  features,  and  astrochemistry 
(by  means  of  sj)ectn.mi  analysis)  of  the  chemical  nature 

457 


THE    WONDERS    OF    LIFE 

of  the  other  heavenly  bodies.  The  monism  of  the  physi- 
cal universe  has  now  been  established. 

Geology  Vv^as  not  developed  into  an  independent 
science  until  towards  the  end  of  the  eighteenth  century, 
and  did  not  extinguish  the  earlier  notion  of  the  creation 
of  the  earth  until  after  1830,  when  the  principle  of  con- 
tinuity and  evolution  was  established.  The  oldest  part 
of  the  science  is  mineralogy ;  the  great  practical  value  of 
the  rocks,  and  especially  the  metals  obtained  from  them, 
having  appealed  to  man's  interest  thousands  of  years 
ago.  In  the  Stone  Age,  Bronze  Age,  Iron  Age,  etc.,  the 
material  for  weapons  and  tools  was  provided  by  stone 
and  metal.  Afterwards  the  development  of  mining  led 
to  a  closer  acquaintance  with  these  metals.  But  no 
notice  was  taken  of  the  fossil  remains  of  animals  and 
plants  until  the  close  of  the  Middle  Ages.  It  was  not 
until  the  eighteenth  century  that  students  began  to  per- 
ceive the  great  significance  of  these  "creation-medals," 
and  at  the  beginning  of  the  nineteenth  paleontology 
arose  as  an  independent  science,  and  proved  equally 
important  to  geology  and  biology.  Other  branches  of 
geology,  such  as  crystallography,  have  also  made  con- 
siderable progress  during  the  last  half-century,  with  the 
aid  of  physics  and  chemistry.  All  these  sections  of 
geology,  especially  geogeny,  or  the  science  of  the  natural 
development  of  the  earth,  are  now  recognized  to  be 
purely  monistic  sciences. 

In  the  five  branches  of  science  I  have  enumerated, 
pure  monism  has  been  universally  and  exclusively  ad- 
mitted (as  far  as  they  relate  to  inorganic  nature)  in 
the  second  half  of  the  nineteenth  century.  There  is 
no  question  in  them  to-day  of  the  wisdom  and  power  of 
the  Creator.  This  is  equally  true  of  geology,  astronomy, 
mathematics,  chemistry,  and  physics.  It  is  otherwise 
with  the  remaining  sciences  which  deal  with  organic 
nature;  in  these  we  have  not  yet  succeeded  in  giving  a 

458 


MONISM 

physical  explanation  and  mathematical  formulation  of 
all  phenomena.  Hence  vitalism  enters  with  its  dualis- 
tic  notions,  and  splits  the  science  into  two  different 
branches — natural  science  (physics  in  the  wider  sense) 
and  mental  science  (metaphysics) ;  fixed  natural  laws 
are  supposed  to  rule  only  in  the  former,  while  in  the 
latter  we  still  have  the  "freedom"  of  the  spirit  and  the 
supernatural.  This  applies,  first  of  all,  to  biology  in 
the  broadest  sense  (including  anthropology  and  all  the 
sciences  that  relate  to  man).  In  the  preceding  chapters 
of  biological  philosoi)hy  we  have  sought  to  refute  vital- 
ism in  every  form,  and  to  secure  the  exclusive  acceptance 
of  monism  and  mechanicism  in  every  branch  of  the 
science  of  life. 

Anthropology  is  still,  as  it  has  been  for  centuries, 
taken  in  many  different  senses.  In  the  widest  sense,  it 
embraces  the  whole  vast  science  of  man,  just  as  zoology 
(in  my  opinion)  deals  with  all  parts  of  the  animal  world. 
Since  I  regard  anthropology  as  a  part  of  zoology,  I 
naturally  extend  the  principles  of  monism  to  both. 
However,  this  general  monistic  conception  of  the  science 
of  man  has  met  with  only  a  restricted  acceptance  up  to 
the  present.  As  a  rule,  the  term  "  anthro])ology "  is 
restricted  to  the  natural  history  of  man,  which  includes 
the  anatomy  and  physiology  of  the  human  organism, 
embryology,  prehistoric  research,  and  a  small  part  of 
psychology.  But  this  "official  anthropology,"  as  most 
of  our  anthropological  societies  (especially  in  Gemiany) 
conceive  it,  generally  excludes  phylogeny,  the  greater 
part  of  psychology,  and  all  the  mental  sciences,  which 
are  regarded  as  metaphysical  in  the  narrower  sense.  I 
endeavored  to  show  in  my  Antliropof^cny  thirty  years 
ago  that  man  (as  a  placental  mammal  of  the  order  of 
primates)  is  no  less  unified  an  organism  (with  body  and 
soul)  than  any  other  vertebrate,  and  that,  therefore,  every 
aspect  of  his  being  should  be  dealt  with  monistically. 

459 


THE    WONDERS    OF    LIFE 

As  is  well  known,  the  views  of  experts  and  laymen 
alike  are  very  much  divided  as  to  the  place  of  psychol- 
ogy in  the  scheme  of  the  sciences.  The  great  majority 
of  the  professional  psychologists,  and  of  educated  people 
generally,  adhere  still  to  the  antiquated  dogma,  with  its 
religious  foundation,  that  man's  soul  is  immortal  and  an 
independent  immaterial  entity.  This  dualistic  view  has 
been  supported  in  the  schools  especially  by  the  author- 
ity of  Plato,  Descartes,  and  Kant;  in  religion  by  the 
authority  of  Christ,  Paul,  and  Mohammed ;  in  education 
and  the  state  by  the  authority  of  most  governments; 
and  in  physiology  by  most  of  the  older,  and  even  some 
recent,  physiologists.  On  this  view,  psychology  is  a 
special  mental  science,  having  only  an  external  and 
limited  connection  with  natural  science.  But  modern 
comparative  and  genetic  psychology,  the  anatomy  and 
physiology  of  the  brain,  have,  in  the  course  of  the  last 
forty  years,  established  the  monistic  view  that  psychol- 
ogy is  a  special  branch  of  cerebral  physiology,  and  that 
therefore  all  its  parts  and  their  application  belong  to 
this  section  of  biology.  The  soul  of  man  is  a  physio- 
logical function  of  the  phronema.  As  I  have  fully  ex- 
plained the  monistic  conception  of  psychology  in  chap- 
ters vi.-xi.  of  the  Riddle,  and  supported  it  with  all  the 
arguments  of  anatomy,  physiology,  ontogeny,  and 
phylogeny  in  my  Anthropogeny,  I  need  not  go  further 
into  the  subject. 

The  science  of  language  shares  the  fate  of  its  sister, 
psychology;  by  one  section  of  its  representatives  it  is 
taken  monistically  as  a  natural  science,  and  by  another 
section  it  is  dualistically  conceived  as  a  branch  of  mental 
science.  On  the  old  metaphysical  view,  speech  was 
regarded  as  an  exclusive  property  of  man,  either  a  gift 
of  the  gods  or  an  invention  of  social  man.  But  in  the 
course  of  the  nineteenth  century  the  monistic  and 
physiological  position  that  speech  is  a  function  of  the 

460 


M  O  N  I  S  i\I 

organism,  and  has  been  gradually  developed  like  all 
other  functions,  has  been  established.  The  comparative 
psychology  of  the  higher  animals  showed  that  in  various 
classes  the  thoughts,  feelings,  and  desires  of  the  gre- 
garious animals  are  communicated  partly  by  signs  or 
touch,  partly  by  sounds  (the  chirrup  of  the  cricket,  the 
cry  of  the  frog,  the  whistle  of  many  reptiles,  song  of 
birds  and  singing-apes,  roaring  of  carnivora  and  un- 
gulates, etc.).  The  ontogeny  of  speech  showed  that 
its  gradual  development  in  the  child  is  (in  accordance 
with  the  biogenetic  law)  a  recapitulation  of  its  phylo- 
genetic  process.  Comparative  philology  taught  that  the 
languages  of  the  different  races  have  been  formed  poly- 
phyletically,  or  independently  of  each  other.  The  ex- 
perimental physiology  and  pathology  of  the  l)rain  show- 
ed that  a  definite  small  region  of  the  cortex  (the  Broca 
fissure)  is  the  centre  of  speech,  and  that  this  central 
organ,  in  conjunction  with  other  parts  of  the  phronema 
and  the  larynx  (the  peripheral  organ),  produces  articu- 
late speech. 

Historical  science  is,  like  philology  or  psychology'", 
still  conceived  in  diflferent  senses  by  experts.  Ver}-  often 
history  is  wrongly  taken  to  mean  the  record  of  events 
that  have  occurred  in  the  course  of  the  development  of 
civilized  life — the  history  of  peoples  and  states  (humor- 
ously described  as  "the  history  of  the  world"),  of  civili- 
zation, of  morals,  etc.  This  is  merely  an  anthropo- 
centric  feeling  that  in  the  strictly  scientific  sense  "his- 
tory" can  only  be  used  for  the  record  of  man's  doings. 
In  this  sense  history  is  opposed  to  nature,  the  one  deal- 
ing with  the  province  of  morally  free  phenomena  (with 
preconceived  aim),  and  the  other  comprising  the  prov- 
ince of  natural  law  (without  preconceived  aim).  As  if 
there  were  no  "natural  history,"  or  as  if  cosmogony, 
geology,  ontogeny,  and  phylogeny  were  not  historical 
sciences!     Although  this  dualistic  and  anthropistic  view 

461 


THE    WONDERS    OF    LIFE 

still  prevails  in  our  universities,  and  state  and  Church 
protect  the  venerable  tradition,  there  can  be  no  doubt 
that  sooner  or  later  it  will  be  replaced  by  a  purely  mo- 
nistic philosophy  of  history.  Modern  anthropogeny 
shows  us  the  intimate  connection  between  the  evolution 
of  the  human  individual  and  that  of  the  race;  and  by 
means  of  prehistoric  and  phylogenetic  research  it  joins 
what  is  called  the  history  of  the  world  to  the  stem- 
history  of  the  vertebrates. 

Medicine  belongs  to  the  front  rank  of  practical  or 
applied  sciences.  In  its  long  and  interesting  history  it 
teaches  how  it  is  only  a  monistic  knowledge  of  nature, 
not  a  dualistic  notion  of  revelation,  that  affords  the 
foundations  of  true  science  and  the  profitable  application 
of  this  to  the  most  important  aspects  of  practical  life. 
Medicine  was  originally  the  business  of  the  priests,  and 
for  thousands  of  years  it  was  under  the  influence  of 
mystic  and  superstitious  ideas  which  were  connected 
with  religious  dogmas.  However,  two  thousand  years 
ago  the  great  physicians  of  classic  antiquity  made  a 
serious  effort  to  provide  a  solid  base  for  medical  practice 
by  a  thorough  anatomic  and  physiological  study  of  the 
human  frame.  But  in  the  general  reaction  of  the  Mid- 
dle Ages  superstitious  and  miraculous  ideas  once  more 
defeated  independent  scientific  investigation.  Disease 
was  supposed  to  be  the  work  of  evil  spirits  (as  Christ 
thought)  which  had  to  be  exorcised.  Miracles  are  still 
thought  to  take  place,  even  in  cultured  circles.  I  need 
only  mention  the  wonders  of  patent  medicines,  mag- 
netic cures.  Christian  Science,  and  other  charlatanry. 
However,  the  great  development  of  science  in  the  nine- 
teenth century,  especially  the  astonishing  advance  of 
biology  about  the  middle  of  the  century,  gradually 
shaped  medicine  into  the  monistic  science  which  as- 
suages so  much  pain  and  suffering  in  humanity  to-day. 
Pathology,  the  science  of  disease,  and  therapeutics,  the 

462 


M  O  N  I  S  xM 

rational  science  of  healing,  arc  grounded  now  on  the 
safe  methods  of  physics  and  chemistry  and  a  thorough 
knowledge  of  the  human  organism.  Disease  is  no  long- 
er regarded  as  a  special  entity  that  comes  on  the  body 
like  an  evil  spirit  or  mysterious  organism,  but  is  con- 
ceived as  a  baneful  disturbance  of  its  normal  activity. 
Pathology  is  only  a  branch  of  physiology ;  it  studies  the 
changes  that  take  place  in  the  tissues  and  cells  under 
abnormal  and  dangerous  conditions.  When  the  causes 
of  these  changes  are  poisons  or  foreign  organisms  (such 
as  bacteria  or  amoebae),  the  art  of  healing  has  to  re- 
move them  and  restore  the  normal  equilibrium  of  the 
functions. 

The  science  of  mental  disease  is  a  special  branch  of 
medicine;  it  has  the  same  relation  to  it  as  psychology 
has  to  physiology.  However,  as  pathological  psychology 
it  deserves  special  consideration,  not  only  on  account  of 
its  extreme  practical  importance,  but  also  because  of  its 
theoretical  interest.  The  misleading  dualist  idea  of 
body  and  soul  that  has  perverted  our  notions  of  mental 
life  from  the  oldest  times  has  led  people  to  regard  men- 
tal disorders  as  special  phenomena,  at  one  time  directly 
as  evil  spirits  that  enter  from  without  into  the  human 
body,  at  another  time  as  mysterious  dynamic  occur- 
rences affecting  the  mystic  being  of  the  soul  (indepen- 
dently of  the  body) .  These  dualistic  and  still  wide-spread 
and  mischievous  errors  have  caused  the  most  fatal  mis- 
takes in  the  treatment  of  mental  disease;  they  have  had 
the  most  unfortunate  effect  on  juristic  and  social  and 
other  aspects  of  practical  life.  Rut  the  ground  has  been 
cut  from  under  these  irrational  and  superstitious  ideas 
by  modern  psychiatry,  which  regards  all  mental  disease 
as  a  disorder  of  the  brain,  and  traces  it  to  changes  in 
the  cortex  that  lie  at  the  root  of  all  psychoses  (delusions, 
lunacy,  etc.).  As  we  call  this  central  organ  of  mind  the 
phronema,  we  may  say:  Psychiatry  is  the  pathology 

4^>3 


THE    WONDERS    OF    LIFE 

and  therapeutics  of  the  phronema.  In  many  disorders 
we  have  already  succeeded  in  anatomically  and  chemi- 
cally tracing  the  changes  in  the  psychic  or  phronetal 
cells  (the  neurona  in  the  phronema).  These  acquisi- 
tions of  the  pathological  anatomy  and  physiology  of  the 
phronema  have  a  great  philosophic  interest,  because 
they  throw  a  good  deal  of  light  on  the  monistic  concep- 
tion of  psychic  life.  As  the  greater  part  (sixty  to  ninety 
per  cent.)  of  these  diseases  are  hereditary,  and  they  have 
mostly  been  acquired  gradually  by  the  ancestors  of  the 
patient,  they  also  afford  clear  proof  of  progressive  he- 
redity, or  the  inheritance  of  acquired  characters. 

Thousands  of  years  ago,  when  barbaric  races  began 
to  adapt  themselves  to  civilized  life,  they  had  a  concern 
for  their  bodily  health  and  strength.  In  classic  an- 
tiquity the  care  of  the  body  by  baths,  gymnastic  exer- 
cises, etc.,  was  greatly  developed,  and  connected  with 
religious  ceremonies.  The  splendid  aqueducts  and  baths 
of  Greece  and  Rome  show  how  much  importance  they 
attached  to  the  external  and  internal  use  of  water.  The 
Middle  Ages  brought  reaction  in  this  province  like  so 
many  others.  As  Christianity  depreciated  this  life  and 
said  it  was  merely  a  preparation  for  the  life  to  come,  it 
led  to  a  disdain  of  culture  and  of  nature;  and  as  it  re- 
garded man's  body  only  as  the  temporary  prison  of  his 
immortal  soul,  it  attached  no  importance  to  the  care 
of  it.  The  frightful  plagues  that  swept  away  millions 
of  men  in  the  Middle  Ages  were  only  fought  with  prayer, 
processions,  and  other  superstitious  devices,  instead  of 
with  rational  hygienic  and  sanitary  measures.  We  have 
only  gradually  learned  to  discard  this  superstition.  It 
was  not  until  the  second  half  of  the  nineteenth  century 
that  a  sound  knowledge  of  the  physiological  functions 
and  environment  of  the  organism  induced  people  once 
more  to  have  a  concern  for  bodily  culture.  All  that 
modern  hygiene  now  does  for  the  public  health,  espe- 

464 


M  O  N  I  S  M 

cially  the  improvement  of  the  dwellings  and  food  of  the 
poorer  classes,  the  prevention  of  disease  by  healthier 
habits,  baths,  athletics,  etc.,  can  be  traced  to  the  mo- 
nistic teaching  or  reason,  and  is  altogether  opposed  to 
the  Christian  belief  in  Providence  and  the  dualism  con- 
nected therewith.  The  maxim  of  modern  hygiene  is: 
God  helps  those  who  help  themselves. 

The  remarkable  progress  of  technical  science  in  the 
nineteenth  century,  which  has  stamped  our  age  as  "an 
age  of  machinery,"  is  a  direct  consequence  of  the  im- 
mense advance  of  theoretical  science.  All  the  privi- 
leges and  comforts  which  modern  life  gives  us  are  due 
to  scientific  discoveries,  especially  in  physics  and  chem- 
istry. We  need  only  recall  the  enormous  importance 
of  steam  and  electric  machinery,  modern  mining,  agri- 
culture, and  so  on.  If  by  these  means  modern  industry 
and  international  commerce  have  prospered  beyond  all 
expectations,  we  owe  this  to  the  practical  application 
of  empirical  truths.  "Mental  science"  and  metaphys- 
ical speculation  have  had  nothing  to  do  with  it.  There 
is  no  need  of  further  proof  that  all  the  technical  sciences 
have  a  purely  monistic  character,  like  their  exact  sources, 
physics  and  chemistry. 

The  scientific  development  of  education  is  one  of  the 
greatest  tasks  of  modern  civilization.  The  ideas  tliat 
are  impressed  on  the  mind  in  early  youth  are  most 
persistent,  and  generally  determine  the  direction  of 
thought  and  conduct  for  the  whole  of  life.  Hence  we 
find  the  struggle  l)etween  the  two  philosophic  tendencies 
assuming  the  greatest  practical  imjjortance  in  this  de- 
partment. As  the  priests  were,  thousands  of  years  ago, 
in  the  first  stages  of  civilization,  the  sole  trainers  of  the 
growing  mind,  they  had  charge  of  the  school  as  well  as 
of  medicine.  Religion  was  made  the  chief  foundation 
of  instruction,  and  its  doctrines  were  the  moral  guide  for 
the  whole  of  life.  The  isolated  attempts  that  were  made 
30  465 


THE    WONDERS    OF    LIFE 

by  monistic  philosophy  in  ancient  times  to  destroy  this 
theistic  superstition  had  no  effect  on  the  education  of 
the  young.  In  this  the  duahstic  principles  of  Plato  and 
Aristotle  prevailed,  their  metaphysical  theories  being 
blended  with  the  teaching  of  the  Church.  In  the  Mid- 
dle Ages  the  power  of  the  Roman  priesthood  enforced 
them  everywhere.  And,  although  a  good  deal  of  this 
teaching  lost  its  prestige  at  the  Reformation,  the  in- 
fluence of  the  Church  on  the  school  was  maintained 
down  to  our  own  time.  The  spiritual  power  of  the 
Church  finds  a  useful  ally  in  this  in  the  conservative  at- 
titude of  most  governments.  Throne  and  altar  sup- 
port each  other;  both  dread  the  advance  of  scientific 
inquiry.  In  face  of  this  powerful  dualistic  alliance, 
supported  by  the  mental  apathy  of  the  masses  and  a 
convenient  blind  submission  to  authority,  the  monistic 
system  has  a  difficult  position  to  maintain.  It  will 
only  gain  solid  ground  in  education  when  the  school  is 
divorced  from  the  Church  and  scientific  knowledge  is 
made  the  foundation  of  the  curriculum.  I  have  pointed 
out  in  the  nineteenth  chapter  of  the  Riddle  the  guiding 
principles  to  be  followed  in  this  reform  of  education  in 
opposition  to  the  influence  of  Church  and  state. 

As  we  have  dealt  in  the  eighteenth  chapter  with  mor- 
als and  their  development  from  habit  and  adaptation, 
we  need  only  mention  here  the  contradiction  that  we 
still  find  between  the  monistic  claims  of  pure  reason  and 
the  dualistic  claims  of  practical  reason.  This  has  been 
largely  sustained  by  Kant's  teaching,  but  his  categori- 
cal imperative  has  been  completely  refuted  by  modern 
science.  The  metaphysical  grounding  of  morality  on 
free  will  and  ethical  intuitions  (a  priori)  must  be  re- 
placed by  a  physiological  ethic,  based  on  monistic 
psychology.  As  this  can  no  more  recognize  a  moral 
order  of  the  world  in  history  than  a  loving  Providence 
in  the  life  of  the  individual,  the  monistic  morality  of  the 

466 


M  O  N  1  S  M 

future  must  be  reducible  to  the  laws  of  biology,  and 
especially  of  evolution. 

The  great  importance  that  attaches  to  the  new  science 
of  sociology  is  due  to  its  close  relations  to  theoretical 
anthropology  and  psychology  on  the  one  hand,  and  to 
practical  politics  and  law  on  the  other.  When  we  take 
it  in  the  wider  sense,  human  sociology  joins  on  to  that 
of  the  nearest  mammals.  The  family  life,  marriage, 
and  care  of  the  young'in  the  mammals,  the  formation  of 
herds  in  the  carnivora  and  ungulates  and  of  troops  in 
the  social  apes,  lead  on  to  the  looser  associations  of 
savages  and  barbarians,  and  from  these  to  the  begin- 
nings of  civilization.  The  history  of  these  associations 
is  connected  with  the  social  rules  that  govern  the  inter- 
course of  smaller  and  larger  communities.  In  the  bio- 
logical reduction  of  social  rules  to  the  natural  laws  of 
heredity  and  adaptation,  dynamic  sociology  (as  Lester 
Ward  has  called  it)  proceeds  on  purely  monistic  lines, 
while  in  social  intercourse  itself  we  still  find  a  good  deal 
of  duahsm.  How  little  truth  and  nature  count  for  in 
our  cultured  society,  how  much  hypocrisy  and  insin- 
cerity have  to  do  with  social  rules,  has  been  well  shown 
by  Max  Nordau  in  his  Conventional  Lies  of  Civilization. 

Politics  is  closely  connected  with  sociology  on  the  one 
hand  and  law  on  the  other.  As  internal  politics  it  con- 
trols the  organization  of  the  state  by  a  constitution; 
as  external  or  foreign  politics  it  directs  the  relations  of 
states  to  each  other.  In  my  opinion,  pure  reason  should 
prevail  in  both  departments;  the  relations  of  the  citizens 
to  each  other  and  to  the  whole  should  be  regulated  by 
the  same  ethical  principles  that  we  recognize  in  personal 
intercourse.  We  are.  unfortunately,  very  far  from  this 
ideal  in  the  life  of  a  modern  state.  Hrutal  egoism  rules 
in  foreign  politics;  every  nation  thinks  only  of  its  own 
advantage,  and  furthers  it  with  all  its  military  and 
other  resources.     Domestic  politics  is  still   largely   di- 

467 


THE    WONDERS    OF    LIFE 

rected  by  the  barbaric  prejudices  of  the  Middle  Ages. 
Great  struggles  are  in  progress  between  the  central 
government  and  the  mass  of  the  people.  Both  parties 
spend  themselves  in  fruitless  conflicts ;  yet  reason  in  the 
life  of  the  state  suffers  more  than  its  special  political 
complexion.  "Whether  the  state  shall  be  a  monarchy 
or  a  republic,  aristocratic  or  democratic,  are  subordinate 
questions.  The  great  question  is:  Shall  the  modern 
state  be  spiritual  or  secular?  Shall  it  be  governed 
theocratically  by  irrational  beliefs  and  clerical  arbitrari- 
ness, or  nomocratically  by  rational  laws  and  civic  right?" 
{Riddle,  chapter  i.). 

In  the  science  of  law,  too,  we  find  the  prevalence  of 
the  dualistic  principles  that  have  come  down  from  the 
Middle  Ages  and  antiquity,  and  have  acquired  a  certain 
sacredness  by  blending  with  the  teaching  of  the  Church. 
Kant's  dualism  is  again  found  to  be  at  work,  influenc- 
ing the  ideas  of  jurists  and  statesmen.  With  it  we  find 
in  our  codes  many  carefully  preserved  relics  of  mediaeval 
superstition.  A  great  deal  of  harm  is  done  by  this  re- 
ligious influence.  Every  day  we  read  in  the  papers  of 
curious  deliverances  in  the  lower  and  higher  courts  at 
which  every  thoughtful  man  can  only  shake  his  head. 
Here  also  there  will  be  no  solid  improvement  until  the 
education  of  jurists  includes  a  thorough  training  in 
anthropology  and  psychology  as  well  as  in  the  code. 

Theology  has  stood  at  the  head  of  the  four  venerable 
"faculties"  at  our  universities  for  centuries.  It  still 
holds  this  place  of  honor,  as  the  Church,  the  organ  of 
practical  theology,  continues  to  exercise  a  profound  in- 
fluence on  life.  In  fact,  most  of  the  other  branches  of 
applied  science — especially  jurisprudence,  politics,  ethics, 
and  pedagogics  —  are  still  more  or  less  affected  by  re- 
ligious prejudices.  The  chief  of  these  is  the  idea  of  God 
conceived  in  some  form  or  other  as  the  Supreme  Being; 
as  Goethe  says,  "Every  one  calls  the  best  he  knows  his 

468 


MONISM 

God."  However,  the  idea  of  God  is  not  the  chief  feat- 
ure of  all  religions.  The  three  greatest  Asiatic  relig- 
ions—  Buddhism,  Brahmanisni,  and  Confucianism  — 
were  at  first  purely  atheistic;  Buddhism  was  at  once 
idealistic  and  pessimistic,  whence  Schopenhauer  regard- 
ed it  as  the  highest  of  all  religions.  On  the  other  hand, 
belief  in  a  personal  God  is  the  central  feature  of  the 
three  great  Mediterranean  religions.  This  anthropo- 
morphic God  is  conceived  in  a  hundred  forms  in  the 
various  sects  of  the  Mosaic,  Christian,  and  Mohammedan 
religions,  but  his  existence  remains  one  of  the  chief  ar- 
ticles of  faith.  No  evidence  of  his  existence  is  to  be 
found;  this  was  very  ably  shown  by  Kant,  although  he 
thought  that  practical  reason  postulated  it.  All  that 
revelation  is  supposed  to  teach  us  on  the  matter  belongs 
to  the  region  of  fiction.  The  whole  field  of  theology, 
especially  dogmatic  theology,  and  the  whole  of  the 
Church  teaching  based  on  it,  are  based  on  dualistic 
metaphysics  and  superstitious  traditions.  It  is  no  long- 
er a  serious  subject  of  scientific  treatment.  On  the  other 
hand,  comparative  religion  is  a  very  important  branch  of 
theoretical  theology.  It  deals  with  the  origin,  develop- 
ment, and  significance  of  religion  on  the  basis  of  modern 
anthropology,  ethnology,  psychology,  and  history.  When 
we  study  without  prejudice  the  results  of  these  sciences 
bearing  on  religion,  theology  turns  out  to  be  pantheism, 
in  the  sense  of  Spinoza  and  Goethe,  and  thus  monism 
becomes  a  connecting  link  between  religion  and  science. 
This  brief  survey  of  the  twenty  chief  branches  of 
modern  science  and  their  relation  to  monism  and  dual- 
ism shows  that  we  are  face  to  face  with  great  contra- 
dictions, and  that  we  are  still  far  from  the  harmonious 
and  successful  adjustment  of  these  differences.  Thev 
are  partly  due  to  a  real  antinomy  of  reason  in  the 
Kantist  sense — an  antithesis  in  ideas,  in  which  the  posi- 
tive seems  to  be  just  as  capable  of  j^roof  as  its  contra- 

469 


THE    WONDER  wS    OF    LIFE 

dictory.  But,  for  the  most  part,  this  unfortunate  an- 
tinomy in  the  sciences  is  connected  with  their  historical 
development.  Pure  reason,  the  highest  quahty  of  civ- 
iHzed  man,  was  gradually  evolved  from  the  intelligence  of 
the  savage,  and  this  in  turn  from  the  instincts  of  the 
apes  and  lower  mammals ;  and  many  relics  of  its  former 
lower  condition  remain  to-day,  and  have,  through  prac- 
tical reason,  a  most  prejudicial  influence  on  science. 
These  dualistic  prejudices  and  irrational  dogmas — in- 
tellectual residua  of  the  primitive  condition  of  the  race, 
fossil  ideas  and  rudimentary  instincts — still  pervade  the 
whole  of  modern  theology,  jurisprudence,  politics,  ethics, 
psychology,  and  anthropology.  If  we  glance  at  the 
whole  field  of  modern  science  at  the  beginning  of  the 
twentieth  century  in  this  connection,  we  can  distribute 
its  twenty  sections  into  three  groups — rational  (purely 
monistic),  semi-dogmatic  (half -monistic) ,  and  dogmatic 
(predominantly  dualistic)  disciplines. 

The  following  may  be  classed  as  rational  or  purely 
monistic  sciences,  in  which  no  competent  and  thorough- 
ly expert  representative  now  admits  dualistic  consid- 
erations: of  the  pure  or  theoretical  sciences,  physics, 
chemistry,  mathematics,  astronomy,  and  geology;  of 
the  applied  or  practical  sciences,  medicine,  hygiene,  and 
technology.  On  the  other  hand,  in  the  semi-dogmatic 
sciences  we  still  find  a  mixture  of  monistic  and  dualistic 
ideas  in  the  appreciation  of  their  aims  and  objects,  one 
or  the  other  prevailing  according  to  the  party  position 
or  personal  training  of  the  individual  representative. 
This  is  the  case  with  most  of  the  biological  sciences, 
biology  (in  the  broadest  sense),  anthropology,  psychol- 
ogy, philology,  history,  psychiatry;  and  of  the  applied 
sciences,  pedagogics  and  ethics.  The  two  latter  sciences 
form  a  transition  to  the  four  purely  dogmatic  sciences 
in  which  the  traditional  dualism  is  still  paramount: 
sociology,    politics,    jurisprudence,    and    theology.     In 

470 


M  U  X  I  S  M 

these  branches  of  science  mediaeval  traditions  retain  a 
good  deal  of  their  power.  Most  of  their  ollicial  repre- 
sentatives cling  to  prejudices  and  superstitions  of  all 
sorts,  and  very  slowly  and  gradually  admit  the  ac- 
quisitions of  pure  reason  as  embodied  in  monistic  an- 
throj^ology  and  psychology.  The  intellectual  life  was 
in  many  respects  more  advanced  at  the  beginning  of  the 
nineteenth  than  of  the  twentieth  century. 

This  classification  of  the  chief  branches  of  knowledge 
in  their  relation  to  philosophy,  the  comprehensive  science 
of  general  truths,  is  naturally  only  a  provisional  and 
personal  sketch.  It  is  especially  dithcult  from  the  cir- 
cumstance that  all  the  sciences  have  very  complex  rela- 
tions to  each  other,  and  have  undergone  many  changes 
as  to  their  aims  and  subjects  in  the  course  of  their  his- 
torical development.  I  will  only  point  out  that  a  good 
deal  of  science — in  fact,  the  rational  sciences  with  exact 
mathematical  basis  —  have  now  been  comi)letely  won 
over  to  monism;  and  in  the  semi-dogmatic  sciences  it 
is  gaining  ground  from  day  to  day,  so  that  we  may  hope 
sooner  or  later  to  see  the  four  dogmatic  sciences  also, 
the  strong  bulwarks  of  dualism  —  sociology,  politics, 
jurisprudence,  and  theolog}'' — succumb  to  monism.  For 
the  ultimate  aim  of  all  the  sciences  can  only  be  the 
unitv  of  their  underlying  principles,  or  their  harmonious 
unification  by  pure  reason. 

It  is  now  more  and  more  generally  acknowledged  in 
educated  countries  that  a  complete  reform  of  our  educa- 
tional curriculum  is  needed,  both  in  elementary  and 
secondary  schools  and  at  the  universities.  The  great 
struggle  between  two  different  tendencies  assumes  larger 
proportions  ever}'  day.  On  the  one  hand,  most  govern- 
ments, following  their  conservative  instinct,  cling  as  fnr 
as  possible  to  mediaeval  traditions,  and  find  support  in 
the  dogmatic  teaching  of  theology  and  jurisprudence. 
On  the  other  hand,  the  representatives  of  pure  reason 

471 


THE    WONDERS    OF    LIFE 

seek  to  get  rid  of  these  fetters,  and  to  introduce  the 
empirical  and  critical  methods  of  modern  science  and 
medicine  into  what  are  called  the  mental  sciences.  The 
opposition  between  the  two  parties  is  accentuated  by 
their  different  sociological  tendencies.  Liberal  human- 
ists claim  that  the  freedom  and  education  of  all  men  is 
the  aim  of  progressive  evolution,  in  the  conviction  that 
the  free  development  of  the  personality  of  each  individual 
is  the  surest  guarantee  of  happiness.  To  conservative 
governments  this  is  a  matter  of  indifference ;  they  look 
on  the  individual  citizens,  in  accordance  with  the  mani- 
fold division  of  labor,  merely  as  so  many  screws  and 
wheels  in  the  great  organism  of  the  state.  The  "upper 
ten  thousand"  naturally  think  of  their  own  welfare  first, 
and  desire  to  keep  all  higher  education  to  themselves. 
But  in  the  light  of  pure  reason  the  state  is  not  an  end 
in  itself;  it  is  a  means  to  insure  the  prosperity  of  the 
citizens.  To  each  of  these,  whatever  their  condition, 
the  opportunity  should  be  afforded  of  acquiring  the 
higher  education  and  developing  their  talents.  Hence  in 
education  we  should  impart  a  general  outlook  on  all  the 
sides  of  human  life.  Each  should  acquire  the  elements 
of  science,  not  only  of  physics  and  chemistry,  but  also  of 
biology  and  anthropology.  On  the  other  hand,  the  pre- 
dominance of  the  classical  training  over  modern  ought 
to  be  restricted.  Every  student  and  every  faculty 
should  be  occupied  with  only  philosophy  and  science  in 
the  first  sessions,  and  not  take  up  special  studies  until 
afterwards. 

At  the  close  of  the  Riddle  I  brought  out  in  clear  relief 
the  antagonism  between  modern  monism  and  traditional 
dualism,  but  also  pointed  out  that 

this  strenuous  opposition  may  be  toned  down  to  a  certain  degree 
oh  clear  and  logical  reflection — may,  indeed,  be  converted  into 
a  friendly  harmony.  In  a  thoroughly  logical  mind,  applying 
the  highest  principles  with  equal  force  in  the  entire  field  of  the 

472 


MONISM 

cosmos — in  both  organic  and  inorganic  nature — the  antithetical 
positions  of  theism  and  pantheism,  vitahsm  and  mechanism, 
approach  until  they  touch  each  other.  Unfortunately,  con- 
secutive thouj,dit  is  a  rare  phenomenon  in  nature. 

This  conciliatory  disposition  has  grown  stronger  and 
stronger  in  me.  Every  year  increases  my  belief  that 
the  dualism  of  Kant  and  the  prevalent  metajihysical 
school  must  give  way  to  the  monism  of  Goethe  and  the 
rising  pantheistic  tendency.  In  this  we  do  not  lose 
sight  of  our  ideals.  On  the  contrary,  our  "realist  phi- 
losophy of  life"  teaches  us  that  they  are  rooted  deep  in 
human  nature.  While  occupying  ourselves  with  the 
ideal  world  in  art  and  poetry,  and  cultivating  the  play 
of  emotion,  we  persist,  nevertheless,  in  thinking  that 
the  real  world,  the  object  of  science,  can  be  truly  known 
only  by  experience  and  pure  reason.  Truth  and  poetry 
are  then  united  in  the  perfect  harmony  of  monism. 


tD.  H.  H\LL  UBPARY 
j^9rU^  ^rglina  SUtd  Collega 


I  N  D  E  X 


Abiogenesis,  339-35S;  may 
still  occur,  357. 

Abiology,  27,  78. 

Abortion.  325. 

Abstraction,  power  of,  316. 

Achromin,   140,   142. 

Acquired  characters,  inheri- 
tance of,  367-36Q,  376. 

Actinal  beauty,   1S5. 

Active  movements  in  organ- 
isms, 262. 

Adaptation,  415. 

i^sthesis,  296,  308. 

^sthetal  cells,  14. 

-Esthetic  selection,  422. 

Agassiz  on  the  creation  of 
species,  30. 

Agnostic  position  on  the  origin 
of  Hfe.  33ii. 

Albumin,  39,   126,  128. 

Albuminoids,  the,  39,  125,  126. 

Alg.ne,   161.   195.  220. 

Alimentary  system,  the,  227. 

Allopula,  174. 

Alternation  of  generations,  253. 

Altmann  on  the  structure  of 
plasm,    134. 

Altruism,  sources  of,  115. 

Ambulacra!  system,   280. 

Am(JL'b<)id  movements,  268. 

Amphigony,   240. 

Amphimixis,  244. 

Amphithecta,    176. 

Angiuphyta,   220. 

Animal  states,  36,  148,  150, 
168. 

Animals,  kindness  to,  115; 
younger  than  plants,  216. 

4 


Animism.   58. 

Annelids,   motor  apparatus  of 

the.   281. 
Antheridia.   249. 
Anthophyta,    162,   220. 
Anthropogcny,  The,  283,  320. 
Anthropogeny,   the  science  of, 

321.  33^-  . 
Anthropologists  and  evolution, 

321. 

Anthropology,  86.  478. 

Anti-vitalism.    50. 

Ape.  mind  in  the,  332,  ii:^. 

Apes  and  men.  common  struct- 
ure of,  285. 

Aphanocapsa,  32,  130,  182, 
196.   205. 

Apostles'  Creed,  the.  60-65. 

Apotelia,    163. 

Apposition,  42. 

Archegonia,   249. 

Archigonv.  341-358;  formula- 
tion 01,  355,  356;  rc})clitic)n 
of,  356;  statement  of  grounds, 
341;  theories  of.  343-34S 

Archiplasm.  129,  142,  158. 

Aristotle.   66. 

Art,  mcnlern  development  of, 
407. 

Articulates,  motor  apparatus 
o{  the.  282. 

Articulation.   281. 

Asexual  generation,  241-244. 

Assimilation.  42.  211. 

Association-contres.    12,  13. 

Associational  l>eauty,  185. 

Astrularva,   279. 

Astronomy,  monism  of,  457. 

75 


THE    WONDERS    OF    LIFE 


Astrozoon,  280. 
Asymmetrical  types,  179. 
Auditory  vesicles,  311, 
Autogony,  341. 
Autonomous  movement,  262. 

Bacilli,  200,  201,  202. 

Bacon,  the  founder  of  empiri- 
cism, 7. 

Bacteria,  the,  157,  198-206, 
218,  234,  235;  absence  of 
nucleus  in  the,  200,  201. 

Bacteriology,  198. 

Baptism,  425,  426. 

Barbarians,  higher,  395;  life  of, 
394;  lower,  394;  mental  life 
of,  58;  middle,  395;  religion 

of,   58. 
Bar^sthesis,  309, 
Barotaxis,  309. 
Bathybius  Haeckelii,  207. 
Beauty,  evolution  of  the  sense 

of,     188;     sources    of,     184; 

stages  of,  184-187. 
Beggiatoa,  199,  205,  218. 
Berzelius  on  catalysis,  44. 
Bilateral-radial  types,  177. 
Bilateral  symmetry,  177. 
Bioblasts,   134. 
Bio-crystals,  41. 
Biogen-hypothesis  of  Verwom, 

46,  137,  138. 
Biogens,  102,  128,  137,  192. 
Biogenetic  law,   the,   380-382, 

384. 

Biogeny,  94,  360. 

Biology,  division  of,  94;  sphere 
of,  27,  78. 

Bionomy,  78,  95. 

Bionta,  149,  151;  virtual,  151; 
partial,  151. 

Biophora,  137, 

Biotonus,   103. 

Blastoderm,  the,  161. 

Botanists  and  zoologists,  diver- 
gence of,  374. 

Brain,  as  an  organ  of  mind,  25; 
evolution  of  the,  22,  327, 
328. 

Brownian  movement,  260. 


Bryophyta,  162, 
Budding,  242,  243. 
Bunge,  as  vitalist,  50. 
Biitschli  on  the  monera,  31 ;  on 
the  structure  of  plasm,  132. 

Calymma,  the,  270. 

Canon  law,  the,  324,  325. 

Carbon  assimilation,  34,  130, 
212,  213,  342. 

Carbon,  importance  of,  37,  38. 

Caryokinesis,  139,  267. 

Caryolymph,  141,  142. 

Caryolysis,   268. 

Child,  mind  of  the,  90,  323. 

Child-soul,  study  of  the,  20. 

Children,  destruction  of  in- 
curable,  21,   120. 

Chi  tine,   282, 

Chlorophyll,  33,  141,  195,  214. 

Chorology,  95. 

Chromacea,  32,  130,  137,  157, 
182,  194-197;  description  of 
the,    194;    structure    of   the, 

^197- 

Chromatella,  33,  343. 

Chromatin,  140,  142. 

Chromatophora,  33.  343. 

Chromoplasts,  141,  196. 

Chroococcacea,  the,  32,  182. 

Chroococcus,  32,  130,  182,  196, 

197,  208. 
Ciliary  movement,  272,  276, 
Circulation  of  the  blood,  228. 
Civilization,  characteristics  of 

58-59;  evils  of,  114;  growth 

of,    334;   modern,    335,   402; 

shades  of,  401 ,  408 ;  stages  of, 

398;  progress  of,  469;  value 

of,  309. 
Civilized    races,    higher,     397; 

life     of,     396;     lower,     396; 

middle,  396;  mind  in,  334. 
Cleanliness  in  antiquity,  464. 
Clothing,     beginning    of,    423; 

fashions  in,  430. 
Cnidaria,    224;    generation    of 

the,  250,  253. 
Coelenteria,  166,  221,  223,  225. 
Coeloma,  the,  223,  225. 


476 


INDEX 


Coelomaria,   i66,  221,  225. 

Cfcnobia,  160,  161. 

Colloids,  nature  of,  39. 

Colon,  the,  226. 

Coloring  methods.  208. 

Conjugation,   246. 

Consciousness  a  function  of  the 
brain,  331;  development  of, 
331;  nature  of,  19,  23,  290, 
291. 

Conservatism  of  governments, 

73- 
Contact-action,  45, 

Copulation,   251. 

Cormophyta,  165,  167. 

Cormus,  36,  148,  150,  154,  168, 

184. 

Corset,  the,  430. 

Cortex   of  the  brain,    12,   323, 

327.   329- 

Cosmic  intelligence,  30;  mon- 
ism, 37. 

Cosmogony,  360. 

Cosmokinesis,   266. 

Craniota,  mind  in  the,  326. 

Creationism,  337. 

Crustacea,  parasitic,  237. 

Crystals,  41;  forms  of,  172; 
growth  of,  42,  43;  life  of,  41 ; 
and  organisms  compared, 
35,  40,  41,  43.  44;  repro- 
duction of,  44. 

Crystallization,  265,  266. 

Crystalloids,  nature  of,  39. 

Culmus,  the,  165,  183. 

Cultivated  races,  definition  of, 
397;  higher,  400;  lower,  398; 
middle,  399. 

Custom,  tyranny  of,  421. 

Cuticle.    146. 

Cyanogen,  346. 

theory,  347- 

Cytodes,  33,  157.  192,  194. 

Cytology,  128,  190. 

Cytophyta,   220. 

Cytoplasm.  35,  122,  138,  139, 
142,   158,   191. 

Cytosoma,  122,  138. 

Cytotheca,   145. 

Cytula,   244. 


Darwin  on  the  origin  of  life, 

^.^>^:   . 
Darwinism,    50,    80,   361,   363, 

364..  373 

De  Bries  on  heredity.  373. 

Death,  nature  af,  98;  of  the 
unicellulars.  99;  of  the  his- 
tona,  100;  real  cause  of,  loi  ; 
total  and  partial,  105. 

Decomposability  of  plasm.  345. 

Descartes'  idea  of  the  soul,  16, 
18. 

Descriptive  science.  4,  5.  6. 

Design,  argument  for,  388. 

Dialysis,  39. 

Diatomes.  41,   182. 

Diclinism,  247. 

Diofcia,   248. 

Disassimilation,   212. 

Disease,  nature  of,  106. 

Dissogony,   252. 

Division  of  labor,  35;  in  the 
cell.  143,  158;  in  the  or- 
ganism. 149,  167;  in  the 
state,   150,   169. 

Divorce,  428.  429. 

Dogmatic  sciences.  470. 

Dominants,  the.  of  Reinke, 
264. 

Driesch.  as  vitalist,  51. 

Dualism.  81 ,  91 .  433. 

Dualistic  view  of  life,  337.  348, 
366;  of  the  mind.  332;  of 
morality,  411;  of  sensation, 
446.  447. 

Dumas.  Louis,  as  vitalist.  47. 

Duty  an  evolved  sense,  413. 

Dwarf  races.  422. 

Dynamism,  85.  110. 

Ear,  canals  in   the.   311;   the, 

Ecninoderms.  motor  organs  of 
the.  279-281. 

Ectogcncsis,  369. 

Education,  reform  of.  471; 
Struggle  o\cr.  465. 

Egoism.  115,  403;  and  al- 
truism. 419. 

Elasticity,  310. 


477 


THE    WONDERS    OF    LIFE 


Eleatic  philosophers,  the,  66. 
Electric  organs,  313. 
Electricity,  sensation    of,  312, 

Elements,  chemical,  37,  38. 

Embryo,  legal  view  of  the, 
325,  326;  mind  in  the,  325. 

Embryology,  20,  21;  mechan- 
ical, 383^ 

End  of  life,  387. 

Energism,  85. 

Energy  as  attribute  of  sub- 
stance, 446,  449;  definition 
of,  449. 

Enzyma,  46,  128. 

Epicureanism,  83. 

Epitelia,   163. 

Epithelium,  ciliated  and  flagel- 
lated,  276. 

Erect  posture,  the,  285. 

Ergology,  95. 

Ergonomy,  35,   150. 

Erotic  chemotropism,  306. 

Eternity  hypothesis  of  life,  338. 

Ethic,  the  perfect,  400. 

Ethics,  411. 

Eucharist,  the,  426. 

Excretion,  232,  233. 

Experience,  importance  of,   3, 

Experiment,  limited  use  of, 
352,353.  383;  nature  of,  7,  8. 

Experimental  science,  4,8. 

Extension,  446,  448. 

Eye,  the,  298;  evolution  of, 
298,  299. 

Faith,  437,  439;  natural  and 

supernatural,  54, 
Family,  evolution  of  the,  402. 
Fashion,  422. 
Fechner  on  sensation,  295;  on 

the  universality  of  life,  340. 
Feeling,  296,  308. 
Fetichism,   57,  58. 
Filar  theory  of  plasm,  134. 
Fistella.  344. 
Flagelliform    movement,     271, 

276. 
Flame,  analysis  of  the,  28. 


Flat-fishes,   metamorphosis  of, 

^78..        . 
Flechsig,  discoveries  of,  13. 
Flemming  on  the  structure  of 

plasm,  133. 
Food,  artificial  production  of, 

400. 
Forms    of    organic    structure, 

173-184. 
Frommann  on  plasm,  133. 
Frothy  theory  of  plasm,   132, 

133. 
Fungi,  162,  204,  215,  234,  236. 
Fungilli,  204,   235. 

Gameta,  the,  244. 
Gastraea  theory,  the,  223. 
Gastraeads,  223. 
Gastric  canal,  228. 
Gastro-canal  system,  222,  223. 
Gastrula,  the,   166. 
Gemmation,  242,  243. 
Genealogy   of  organisms,   304, 

305.  376. 
Generation,  sexual  and  asexual, 

241-251. 
Geogeny,  360. 
Geology,   historical   nature   of, 

378;  monism  of,  458. 
Geotropism,  310. 
Germ-plasm,    143;    the    theory 

of,  367.   372- 

German  mind,  Janus  character 
of,  441. 

Gills,  229,  230. 

Globular  shape,  origin  of,  34. 

Gloeocapsa,  32,  196,  205. 

Goethe,  monism  of,  442;  real- 
ism of,  440 ;  scientific  studies 
of,  440,  441. 

Gonades,   249. 

Gonochorism,   246. 

Gonoducts,   250. 

Granular  theory  of  plasm,  134. 

Gravitation,  sensation  in,  309. 

Growth,   241. 

Growth  movements,  264. 

Habit.  415-417;  in  inorganic 
bodies,  417. 


478 


I  N  D  I-:  X 


Heart,  the.   228;  work  of  the, 

277- 
Heat,  sensation  of,  300,  301. 
Heaven,    109. 
Hedonism,  84. 
Hehotropism,   298. 
Ilelmholtz  on  the  origin  of  Hfe, 

339- 
Herachtus  on  hfe,  28. 

Heredity,  conservative  and  pro- 
gressive, 368;  cumulative. 
369;  theories  of,  135,  136, 
366. 

Hermaphrodism,  245,  246,  258, 

259- 
Hermaphroditic  glands,  249. 
Hertwig,  O.,  on  the  biogenetic 

law,   382  ;    on    the    monera, 

31- 
Heterogenesis,   254. 

His,  W.,  theories  of,  ;^8^. 

Histolysis,   106. 

Histona,  the,  36. 

Histonals,  165,  166,  171,  182. 

Historical  waves,  389. 

History,  461;  nature  of,  9; 
sources  of,  9. 

Hofmeister  on  organic  chemis- 
try. 45- 

Holosphnera.    173. 

Honor,  false  sense  of,  430. 

Huxley  on  organic  individual- 
ity,   152. 

Hyaloplasm.    130,    143. 

Hybrids,  255,  256;  fertility  of, 

Hydrf>static  movements,  270. 
Hygiene,  401,  464. 
Hylonism.  82. 
Hylozoism,  8r.  86,  451. 
Hypogenesis,   255. 
Hypotheses,     nature     of,     54; 
necessity    for,    86,    87,    89, 

378.  439- 

Idealism,  theoretical  aiid  prac- 
tical, 84,  92. 

Idiocy,   20. 

Idioplasm  theory,  the,  136,  137, 
366,  367. 


Ileum,  the,  226. 

Imugmation,   function   of   the, 

Imbibition    energy    of    plasm. 

Imbibition  in  organisms,  261. 
Immaterial     world,     the,     436, 

437- 
Immortality,  the  l)elief  in,  64, 

65,     71,     108;    of    the    uni- 

cellulars,  99-101. 
Incurables    and     suicide.     118, 

' }  9  • 
Individuality, organic.  149,  ic2. 
Infusoria,    movement    in    the, 

268,   269,  272. 
Inoculation,   204. 
Insanity,  increase  of,  114,  118, 

119. 
Insectivorous  plants,  304,  305. 
Instinct,  418. 
Intelligence,  316,  317. 
Intercellular  matter,  145. 
Intussuscc|)li<)n,   42. 
Ionic  philosophers,  the.  66. 
Irritability,  287,  288.  291,  293, 
Isopola.    174. 

Ka.vt  as  natural  historian,  9; 
biological  ignorance  of,  11, 
318,  319;  critical  views  of, 
438;  C(jntradictory  views  of. 
68.  434.  444;  influence  of.  25; 
mechanical  views  of,  435; 
moral  j)hilosophv  of.  412, 
413;  mystic  trainmg  of.  443; 
narrow  life  of,  443:  philos- 
ophy of.  68.  6().  74.  434- 
440;  popularity  of.  444: 
theory  of  knowledge  of.  9.  10, 

,'^9.  317-319.  332; 
Kassowitz  on  archijjony.  355. 
Kelvin,   honl.  on  the  oriinn  of 

life.  339. 
Kidneys,   the.   jj^ji. 
KirehhofTon  the  work  of  science. 

(i. 
Knowletlge.    a     priori    and    a 

p<y.s tirinri,    11.    24,    317;    and 

faith  compared,  54;  dualistic 


47Q 


THE    WONDERS    OF    LIFE 


theory  of,  24;  monistic  theory 
of,  12-14. 
Kussmaul  on    the    child -soul, 
20. 

Lamarck,  79. 

Lamarck's  transformism,  363. 

Landscape  beauty,  187. 

Lange  on  Kant,  439. 

Larvae,   253. 

Law,  beginning  of  idea  of,  420; 

reaction  in  science  of,  401. 
Leibnitz,  philosophy  of,  no. 
Leucocytes,  228;  and  bacteria, 

.305- 
Lichens,   238. 

Life,    artificial    production    of, 

352,  358;  as  a  flame,  28,  29; 

constant  change  of,  386,  387  ; 

evolution  of,  360-365;  length 

of,   loi;  nature  of,   27,  343; 

origin  of,  337-358;  value  of, 

386-410. 
Light,  action  of,  297-300. 
Living  substance,  36,  123. 
Lobmonera,  206. 
Localization   of  functions,    17, 

19,  20;  of  mental  functions, 

328,  329. 
Locomotion,  275-285;  modem 

progress  in,  404. 
Lord's  Supper,  the,  426. 
Love,    progressive    refinement 

of,  402. 
Luminous  animals,  312. 
Lungs,   230,  231. 

Machine-theory  of  life,  the, 
29,  30,   102. 

Macrogameton,   244. 

Mammals,  common  descent  of 
the,  284;  motor  apparatus 
of  the,  283. 

Manners  and  morals,  421. 

Marriage,  development  of,  402, 
403 ;  evolution  of,  427 ;  priest- 
ly control  of,  428. 

Materialism,  82,  451. 

Mathematics,  456. 

Matrimony,  427,  428. 


Matter  as  attribute  of  sub- 
stance, 448. 

Mechanical  embryology,  103. 

Mechanics,   259. 

Medicine,  development  of,  462. 

Membranes,  cellular,  144,  145, 
155,   157,   194. 

Memory,  416. 

Mental  disease,  evidential  value 
of,  19. 

Metabolism,  28,  38,  44,  46,  103, 
130,  210,  211,  217;  a  me- 
chanical process,  259,  260; 
in  the  metaphyta,  219-221; 
in  the  metazoa,  221,  233;  in 
the  protophyta,  217-219;  in 
the  protozoa,  219,  220. 

Metagenesis,  253. 

Metamerism,  167,  168,  281. 

Metamorphology,  94. 

Metaphysicians  disdain  phys- 
ical science,  16. 

Metaphysics,  nature  of,  10,  88, 
89. 

Metaphyta,   161,   165. 

Metaplasm,   106,   129. 

Metaplasmosism,   107. 

Metasitism,  217. 

Metazoa,   163. 

Micella,   137,  344. 

Micrococcus,  201,  202. 

Microgameton,   244. 

Middle  Ages,  thought  in  the, 
66,  67. 

Mimicry,  421,  422. 

Mind,  the,  315,  316;  a  function 
of  the  brain,  328-330;  evolu- 
tion of  the,  319,  320,  322,  323, 
326. 

Miracles,  60;  in  biology,  55; 
nature  of,  54. 

Mohl,  Hugo,   122. 

Molecular  structure  of  the  mo- 
nera,  34,  137;  theories  of 
plasm,  342-346. 

Molecules,   126,   127. 

Monaxonia,   174. 

Monera,  the,  31-33,  40,  157, 
182,  190-209,  342. 

Monism,  81,  433-445. 


480 


INDEX 


Monobia,   i6o,   196, 

Monoclinism,   247. 

MoncEcia,  248. 

Monogamy,  240. 

Morality,  411,  412;  a  social 
instinct,  419,  4-20;  conven- 
tional, 430;  evolution  of, 
413,  414,  430-432;  a  form  of 
adaptation,  414. 

Morphology,  94,   171. 

Morphonta,   149,    152. 

Motion  in  metabolism,  259. 

Miiller,  Johannes,  on  the  nat- 
ure of  life,  49;  on  sensation, 
288. 

Muscles,  the,  273,  276-279; 
forms  of  in  lower  animals, 
278;  striated  and  non  -  stri- 
ated,  277. 

Muscular  cells,   277. 

Mutation  theory,  the,  365,  373. 

Myophcena,  269. 

Nageli  on  evolution,  365; 
on  plasm,  137;  on  the  origm 
of  life,  343,  344.  354,.  356;  on 
universality  of  sensation,  450. 

Natural  history,  9. 

Naturalism,  86,  87. 

Necrobiosis,   106,  349. 

Neo-Darwinism,  375,  376. 

Neo-Lamarckism,  375,  376. 

Neo-vitalism,  48;  sceptical  and 
dogmatic,   50. 

Neurona,  12,  13.  328. 

Nitrobacteria,  201,  215,  21S. 

Nuclein,   156. 

Nucleolus,    140. 

Nucleus  of  the  cell,    122,   139, 

Nutrition,  progress  in  supply 
of,  401. 

Observation,    subjective   and 

objective,  7. 
Occultism,   74,   75. 
(Ecology,   78,  95. 
Oken,  Lorentz,  79,  80. 
Olfactory  region,  303. 
Ontogeny,  94,  361,  376,  379. 


Optimism,    109,   iio, 
OrgancUa,    35,    130,    i^n.    163, 

Organic  chemistry,  37;  and  in- 
(jrganic,  ditlerencts  Ijctwccn, 
27,  28,  40;  meaning  of,  37; 
sensations,  302,  308. 

Organism,  nature  of  an,  29,  30, 

Organization,  nature  of,  29; 
progress  of,    338;   stages  of, 

149.  150.  15^- 
Organs,  159,  163;  apparatus  of. 


164; 
1 2. 


of 


164;     systems    of, 
sense  and  thought, 

Osmosis,   39. 

Ostwald,  as  a  monist,  38;  on 
enzyma,  46;  on  growth.  44; 
on  mental  energy,  330;  sys- 
tem of,  85. 

Ovary,  325. 

Ovoplasm,   245. 

Ovulum,  the,  245,  247,  250. 

P.-EDOGENESIS,    253. 

Palavitalism,  48,  49. 

Palingenesis,  3S2. 

Pangenesis  thct)ry,  the,  3O6. 

Panpsychism,  340. 

Pantheism,  82. 

Paranuclein,   141. 

Parasites,   235-238. 

Parasitology,  235. 

Paratonic  movement,  262,  274. 

Parthenogenesis.  251,  252. 

Passive  movements  in  organ- 
isms,  262. 

Pasteur  disproves  spontaneous 
generation,  350-35-- 

Paulospores.   244. 

Peptones,  45. 

Perception  of  stimuli.  292,  293. 
296. 

Perigenesis  of  the  plastidulos, 
136. 

Perjietual  motion  of  uniwfNO, 
25S. 

Persons,  36,  148,  150,  154.  »^6. 
I  S3. 

Pessimism,   109.   iio,    iii. 


31 


481 


THE    WONDERS    OF    LIFE 


Pfliiger  on  origin  of  life,  345, 
346,  356. 

Philology,  461, 

Philosophy,  history  of,  81; 
modern,  defects  of,  453; 
nature  of,  2,  3,  453,  454. 

Phoronomy,   259. 

Photo-synthesis,  214,  217. 

Phototaxis,  298. 

Phronema,  the,  14,  15-17; 
structure  of  the,  329. 

Phroneta,  "the,  13,  329,  331. 

Phronetal  cells,  14,  17. 

Phylogeny,  94,  361,  376,  379; 
sources  of,  377. 

Physicians,  liberal  views  of, 
116-118. 

Physics,  monism  of,  455 ;  nature 
of,  89,  454. 

Physiologists,  dualism  of,  18. 

Physiology,  93. 

Phytomonera,   193. 

Phytoplasm,   213,   217. 

Piano  theory  of  the  soul,  16. 

Pineal  gland,  the,  16. 

Planospores,   244. 

Plants,  spontaneous  movement 
in,   274,   275. 

Plasm,  121,  123,  128-146; 
chemical  constituents  of,  125, 
126;  differentiation  of  the, 
138;  molecules  of,  136;  nat- 
ure of,  27,  28,  159;  structure 
of,   128,   129,   130-138. 

Plasma  products,  144. 

Plasmodomism,  33,  34,  130, 
193,  197,  212,  213,  343,  357. 

Plasmogony,  354. 

Plasmophaga,  193,  196,  200, 
212. 

Plasson,   158. 

Plassonella,  355,  358. 

Plastids,  138,  192. 

Plastidules,   136. 

Plastin,   141. 

Plate  on  Darwinism,  364. 

Platnosphasra,   174. 

Plato,  dualism  of,  436;  philos- 
ophy of,  66. 

Platodes,  225. 

48 


Pleuronectides,   178. 

Poetry,  pedagogical    value   of, 

439- 
Poisonous  bacteria,    221,   305; 

fungi,   236. 
Polioplasm,   130,   143. 
Politics,  467. 
Polytomy,   243. 
Powder,   31. 
Pressure,  sense  of,  310. 
Preyer  on   the   child-soul,    20; 

on  the  earth  as  an  organism, 

37;    on   universality   of   life, 

340. 
Principle  of  individuation,  153. 
Probionta,   354. 
Promorphology,  94,   172. 
Protamoeba,   206. 
Proteids,  126,  127. 
Protestants,  liberalism  among, 

73- 
Protists,  the,  34,  35,  131,  160, 

171,  182,  190-209;  can  en- 
dure extreme  temperatures, 
300;  movements  of  the,  267, 
271;  science  of  the,  92,  93; 
sensitiveness    to    electricity, 

313- 
Protoplasm,  32;  nature  of,  121, 

122,   125. 
Providence,  belief  in,  107,  108. 
Pseudopodia,   268. 
Psychiatry,   19,  329,  463. 
Psychogenesis,  21. 
Psychology,  461;  comparative, 

21,    22;    modem,    errors    of, 

71;  monistic,  322;  nature  of, 

18. 
Psycho-monism,  92. 
Psychophysics,   330. 
Pteridophyta,    162,   220. 
Ptomaines,   203. 
Purposive  movement,  264,  265. 
Pyramidal  types,   176. 

Radiolaria,  41,  156,  172,  181; 

movement  in  the,  322. 
Ranke,  J.,  on  evolution,  322. 
Rational  sciences.  470. 
Reaction,  293. 


I  N  I)  E  X 


Realism,  90,  91. 

Reason,    316,    317;    pure    and 

practical.   317. 
Reason  and  authority,  423. 
Redemption,  dotjma  of,  62. 
Reflex  movement,  262,  263. 
Regeneration,     organic,      loi- 

105- 
Reinke,  as  vitalist,  51;  dualism 

of,  30;  on  the  monera,  31 ;  on 

the  origin  of  life,  337;  theory 

of  dominants,  264;  works  01, 

80,  81. 

Release  of  energy,  294. 

Religion,  evolution  of,  57-65, 
420,  421,  424. 

Reproduction  a  monistic  proc- 
ess, 257;  by  division,  242; 
nature  of,  241. 

Respiration,   228-232. 

Resurrection,  the,  64. 

Resurrection  plants,  262. 

Rhizomonera,   206. 

Rhizopods,  129,  192,  193,  219; 
movement  in  the,  270. 

Rhodocytes.   228. 

Rhumbler,  L.,  on  the  cell-life, 
132. 

Rhythmic  beauty,  185. 

Richter,  H.  E.,  on  life,  339. 

Rindtleisch,  as  vitalist,  51. 

Romanes,  conversion  of,  22,  23. 

Romanism,  63,  425,  426. 

Sacraments,  425,  426. 

Saposites,   234. 

Saprobiosis,   349,  350. 

Sarcode,    155. 

Savage,  mind  in  the,  56,  57, 
90.  333.  391.  405.  406,  424; 
religion  of  the,  57  ;  sense-life  in 
the,  406,  407;   views  of  the, 

390- 
Savages,  higher,  394;  life  of  the, 

392-394;  lower,  398;  middle, 

393- 
Schiller,  idealism  of,  439,  440- 

442. 

Schizophyta,   201. 

Schleiden,   154. 


Schleiermacher,   72. 

Schopenhauer,  as  pessimist. 
Ill,  112;  on  the  categorical 
imperative,  412;  on  suicide, 
I  14. 

Schultze,  Max,  on  the  cell,  155. 

Schwann,    154. 

Science,  confusion  in,  77;  nat- 
ure of,  4;  schools  of,  4; 
work  of,  5,  6;  value  of,  407, 
408. 

Science  and  tradition,  conflict 
of,  70,  71. 

Secretory  movement,  271. 

Selection,  theory  of,  361,  363, 

Self-cleavage,  242. 

Self  -  consciousness,  beginning 
of,  323.  324. 

Semi-dogmatic  sciences.  470. 

Senility,  causes  of,  106. 

Sensation  and  consciousness, 
290,  291,  295. 

Sensation  as  attribute  of  sub- 
stance, 447,  448;  analysis  of, 
293;  common  to  all  bodies, 
295,  296,  309;  ev<ilution  t)f, 
450;  in  atoms,  83;  in  plants, 
292,  304;  nature  of,  287-293; 
neglected  by  physiologists, 
289,  292 ;  of  matter,  302;  uni- 
versal, 449. 

Sensations  in  savage  and  civil- 
ized man,  405,  406;  organic, 
302,  308. 

Sense-centres,  13.  329. 

Senses,  finer  development  of 
the,  406. 

Sensibility.   287,  2S8,  293. 

Sensitiveness.    293. 

Sensorium.  the.    14. 

Sensualism.  4.  14.  15. 

Sentiment  ami  reason.  120. 

Sex  sense,  the,  245. 

Sexual  beauty,   186. 

characters,  secondary,  251. 

generation,  244-253. 

selection .   251. 

sense,  the.  306,  307. 

Shame,  feeling  of.  423. 

Sight,  evolution  fif,   ^\. 


483 


THE    WONDERS    OF    LIFE 


Silicon,  40. 

Skeletal  theory  of  plasm,  133. 

Skeleton,  common  type  of  the, 

371- 
the,  278,279,  283,  284. 

Sleep  of  flowers,  274. 

Smell,  303,  304. 

Snails,   evolution   of  the,    179; 

muscles  of  the,  278. 
Sociology,  467. 
Soul,   the,    315,    324;    dualistic 

idea  of  the,  15,  16;  found  in 

all   substance,    297;    seat   of 

the,  15-18. 
Space,  nature  of,  70;  sense  of, 

311- 
Spallanzani    and    spontaneous 

generation,  350. 

Spartan  selection,  21,  119. 

Specialism,  dangers  of,  92, 

Species,  nature  of  the,  204. 

Speech,  461. 

Sperm-plasm,  245. 

Spermatozoon,  the,  245.  move- 
ment of  the,  271,  272. 

Spinoza,  system  of,  82;  mon- 
ism of,  445. 

Spirilla,   202. 

Spiritism,  74,   75. 

Spiritualism,  451. 

Spontaneous  generation,  348; 
conflict  over,  349,  350;  older 
belief  in,  349. 

Sporangia.,  244. 

Spores,   244. 

Sporozoa,   235. 

Sprouts,  36,  148,  151,  154,  165, 

183- 
State  and  the  individual,  the, 

409. 

States,  modem,  defects  of, 
409,  410. 

Stationary  life  in  animals,  275. 

Stauraxoni  a ,   175. 

Stimuli,  acoustic,  311;  action  of, 
295;  chemical,  301-309:  con- 
duction of,  295,  296;  electric, 
312,313;  gravitational,  309- 
312;  optic,  297-300;  thermic, 
299-302, 


Stock,  the,  168,  184. 
Strauss,  D.  F.,  72, 
Strophogenesis,   254. 
Substance,   attributes   of,   446, 

448;    eternity,    of,    97;    the 

problem  of,  2. 
Suicide,  contradictory  views  of, 

112;    occasional    justice    of, 

112,  113,  1 16. 
Sun-dew,  action  of  the,  304. 
Supernatural,  the,  87,  88. 
vSuperstition,   56. 
Sutherland,    A.,    on    morality, 

392. 
Swimming-bladder,  the,  231. 
Symbiosis,   238. 
Symmetry,   171,   172. 
Sympathy,   115. 

Tailor  theory,  the,  383. 

Tape- worms,   237. 

Taste,   302,   303. 

Technical  science,  progress  of, 

465. 

Tectology,  94. 

Teleology,   181,  366. 

Teleology  in  movement,  265. 

Teleology,  mechanical,  362, 
363. 

Temperature,  perception  of, 
299—301. 

Thallophyta,   161,   165. 

Thallus,  the,  165,  195. 

Theology,  468. 

Thermotaxis,  301. 

Thigmotaxis,  310. 

Thought  as  attribute  of  sub- 
stance, 445. 

Thought  centres,  13,  329. 

Time,  nature  of,   70. 

Tissue  animals,  163 ;  plants,  162. 

Tissues,  primary  and  secondary, 
161,  162. 

Tocogony,   240. 

Touch,  sense  of,  309;  in  plants, 

309.  3TO- 
Tracheata,  the,  231. 

Tradition,  power  of,  423. 

Transgressive    growth,    42,44, 

240,  241. 


484 


INDEX 


Transubstantiation,  426. 
Treviranus,   79. 
Tropesis,   296,  308. 
Trophoplasts,   143. 
Truth,  nature  of,  i,  2,  4. 
Tubingen  school,  the,  72. 
Turgescence    movements,  274, 

275- 
Turgor,  273-275. 

Types  of  organic  structure,  1 7  3- 

184. 

Unequal  value  of  life,  390. 

Value  of  modern  life,  408,  409. 

Variability  in  species,  373. 

Variation  movements,  274. 

Veddahs,  the,  393. 

Vegetal  diet,  227. 

Vertebrates,  mind  in  the.  328; 
motor  apparatus  of  the, 
283,  284;    succession   of  the, 

327- 
Verwom,  Max,  on  enzyma,  46; 

on    the    nature    of    life,    28; 

on  the  origin  of  life,  348. 

Vibratory  movement,  271. 


Virchow  and  evolution,  323;  on 
the  aim  of  science,  5. 

Vital  force,  the,  47-51. 

movement,  266-286. 

Vitalism,  47-51,  459. 

Voluntary  movement  mechan- 
ical, 262-264. 

War,  400,  409. 

Watch  compared  with  organ- 
ism, 30. 

Water-feet,   280. 

Water- vessels,   230. 

Weismann  on  immortality,  99- 
10 1 ;  on  selection,  364;  on  the 
structure  of  plasm,   137. 

Will,  freedom  of  the,  263,  265, 
286. 

Wind-pipe,  the,  232. 

Woman,  improvement  in  posi- 
tion of,  402. 

Zehnder  on  the  origin  of  life 

.344- 
Ziegler  on  instinct,  418. 
Zoomonera,    193,   219. 
Zooplasm,  213. 


THE    END 


■?? 


